What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
iTechGuides is reader-supported. When you buy through links on our site, we may earn an affiliate commission. As an Amazon Associate I earn from qualifying purchases. Learn more
A failing or degraded NAS drive is a time-sensitive loss-of-redundancy event. First identify the exact disk and storage pool, confirm that an independent backup works, and stop unnecessary writes. If the RAID level still has fault tolerance, obtain a compatible NAS-rated replacement that meets your platform’s capacity, interface and sector-format requirements. Then use the NAS’s documented offline, replace and rebuild/resilver workflow, monitor it to completion, and verify that the pool is healthy again.
What a failing or degraded alert means
“Degraded” means the storage pool or RAID set has lost at least one member but is still accessible through its remaining members. Protection is reduced while it is in this state. A further disk failure can exceed the array’s fault tolerance, interrupting access or causing data loss. “Failing” can describe a disk with predictive-health errors, read or write errors, link problems or other faults; the exact meaning depends on the NAS operating system and the alert text.
Do not treat a degraded pool as a harmless warning or as a substitute for backup. RAID keeps a pool available after certain hardware failures; it does not create an independent, historical copy of your files. Your first objective is to preserve the data that exists now, then restore redundancy without causing a second failure.
Stabilize the NAS before touching a disk
Record the evidence
Open the NAS storage-management page and record the alert verbatim. Note the pool, volume or RAID name; bay number; disk model and serial number; reported health state; and whether the pool is online, degraded, read-only or offline. Take screenshots or export the event log. These details prevent removing the wrong member when several disks have similar names.
#1 Best Overall
- Read Before You Buy — No Video Output: These adapters support charging and USB 2.0 data transfer, but cannot transmit video signals. Except for standard USB webcams (which use USB data only), they are not compatible with HDMI/DisplayPort cables, video-capable USB-C hubs, or docking stations with video output.
- Convert USB-A Ports to USB-C: Designed to connect USB-C earphones, cables, flash drives, card readers, and other USB-C accessories to standard USB-A ports. Plug-and-play with no drivers or software required.
- Aluminum Alloy Housing: Built with a sturdy aluminum alloy shell that aids in heat dissipation and protects against daily wear and scratches. Designed to maintain a stable and secure connection.
- Compact & Travel-Friendly: The ultra-compact design allows the adapter to stay plugged into your device without blocking adjacent ports or adding bulk, reducing wear and tear on your original USB ports.
- 12-Month Warranty: Backed by a 12-month manufacturer warranty for peace of mind. Designed to meet strict quality control standards for reliable everyday performance.
Confirm an independent backup
Check that a separate backup exists and can actually be read. A backup job that merely reports “completed” is not enough: open representative files or perform a test restore from the backup target. Prioritize irreplaceable data if capacity or time is limited. If no usable backup exists, copy critical data while the pool is still accessible, but keep the workload as light as possible and stop if read errors increase.
Reduce avoidable workload
Pause large transfers, indexing, virtual machines, media transcoding, snapshots that are not needed for recovery and other intensive jobs. Do not run a disk-wipe, initialize operation or ad-hoc repair command. Never pull a disk solely because a light is amber or a transient message appeared; first let the NAS identify the affected member and show the supported replacement procedure.
Check whether the array can survive the failure
Recovery is possible only while the number and position of failed members remain within the RAID type’s tolerance. Read the pool’s status page rather than guessing from the number of bays. Some systems report a disk as failed, others as missing, faulted or disconnected, and a cabling problem can look like a dead drive.
Quick wins for a faster PC:
Repair Windows errors before they cause bigger problemsFix Now →Scan for outdated or missing drivers - takes under a minuteDriver Scan →Clear out junk files and repair common Windows errorsFree Scan →Rank #2
- 5-in-1 USB-C Hub: Experience comprehensive connectivity featuring a Power Delivery input, two USB-A 2.0 ports, a USB-A 3.0 port, and an HDMI port. (Note: The USB-C power delivery input port is only for connecting an external wall charger to power your laptop and cannot power peripheral devices.)
- 90W Pass-Through Charging: Achieve optimal charging with 90W pass-through power to your laptop, supported by a total input of 100W, with the hub reserving 10W for operational efficiency. (Note: Wall charger not included.)
- Quick Data Transfers: Accelerate your productivity with rapid data transfers using a high-speed 5Gbps USB 3.0 port and two 480Mbps USB 2.0 ports.
- 4K HDMI Display: Enhance your visual experience with a hub capable of delivering 4K resolution at 30Hz in both mirror and extend modes. Please note that this hub is compatible with MacBook (macOS 12 and newer), Windows 10 and 11, ChromeOS, and laptops equipped with DP Alt Mode and Power Delivery. Note: This device is not compatible with Linux.
- What You Get: Anker USB-C Hub (5-in-1, 4K HDMI), welcome guide, 18-month warranty, and our friendly customer service.
| Pool condition | What it tells you | Correct response |
|---|---|---|
| Online/healthy | Redundancy is currently present, although a predictive warning may still require action. | Confirm the warning, verify backups and schedule replacement before the disk becomes unavailable. |
| Degraded but accessible | At least one member is no longer contributing normally; protection is reduced. | Identify the exact member, obtain a qualified replacement and rebuild promptly. |
| Read-only or repeatedly faulting | The system is protecting metadata or data from further damage, or errors exceed routine recovery. | Stop writes and escalate before attempting another replacement. |
| Offline or inaccessible | The pool cannot be mounted with its current members. | Do not experiment with force options; use vendor support or a professional recovery service. |
| Stripe/RAID0 with one failed disk | There is no redundancy to reconstruct the missing member. | Recreate the pool and restore all data from backups. A replacement disk alone cannot rebuild it. |
TrueNAS states that when a disk fails in a Stripe (RAID0) pool, “you must recreate the entire pool and restore all data backups.” For redundant layouts, consult the platform’s fault-tolerance description and make sure no other member is reporting errors before starting a rebuild.
Choose the correct replacement drive
Buy a NAS-rated replacement hard drive, not simply the cheapest disk that fits the bay. Eligibility is model- and platform-dependent, and the replacement process can erase the selected disk. Use the NAS vendor’s compatibility list where available, then compare the following requirements.
| Check | What to verify | Why it matters |
|---|---|---|
| Capacity | At least as large as the failed disk when the platform requires it. TrueNAS explicitly requires the same or greater capacity. | A smaller nominal size, even by a small amount, may be rejected; usable capacity can also differ between models. |
| Interface | SATA or SAS, matching the enclosure, backplane and controller. | A physically similar connector does not guarantee electrical or controller compatibility. |
| Sector format | Native sector size and any 512e or 4Kn requirement stated by the NAS. | An incompatible format can prevent the disk from joining or create performance and alignment problems. |
| Physical fit | Bay size, tray mounting points, height and vibration characteristics. | A drive that cannot seat correctly can appear missing or repeatedly disconnect. |
| Workload rating | A NAS or enterprise model appropriate for the enclosure’s duty cycle, vibration environment and expected workload. | Desktop drives may have unsuitable error-recovery behavior or endurance for a multi-disk array. |
| Warranty and support | Warranty term, regional availability and whether the NAS maker lists the model. | Supportability matters if a rebuild fails or the vendor asks for drive diagnostics. |
| Noise and power | Power draw at spin-up and operating acoustics within the NAS’s limits. | A high spin-up load can destabilize a small enclosure or shared power supply. |
Match the failed disk’s capacity requirement, but do not assume identical brand or model is mandatory unless your platform says so. A larger qualified disk may be accepted, although some arrays reserve only the amount needed to match existing members. Keep the receipt and record the new disk’s serial number before installation.
Rank #3
- Sleek 7-in-1 USB-C Hub: Features an HDMI port, two USB-A 3.0 ports, and a USB-C data port, each providing 5Gbps transfer speeds. It also includes a USB-C PD input port for charging up to 100W and dual SD and TF card slots, all in a compact design.
- Flawless 4K@60Hz Video with HDMI: Delivers exceptional clarity and smoothness with its 4K@60Hz HDMI port, making it ideal for high-definition presentations and entertainment. (Note: Only the HDMI port supports video projection; the USB-C port is for data transfer only.)
- Double Up on Efficiency: The two USB-A 3.0 ports and a USB-C port support a fast 5Gbps data rate, significantly boosting your transfer speeds and improving productivity.
- Fast and Reliable 85W Charging: Offers high-capacity, speedy charging for laptops up to 85W, so you spend less time tethered to an outlet and more time being productive.
- What You Get: Anker USB-C Hub (7-in-1), welcome guide, 18-month warranty, and our friendly customer service.
Replace and rebuild safely
TrueNAS
- In the storage dashboard, open the affected pool and confirm the disk identity by serial number and slot.
- Use the disk action that takes the failed member offline. TrueNAS recommends offlining before physical removal so the system records the intended state.
- Power down only if your enclosure requires it; otherwise follow its hot-swap instructions and remove the confirmed disk.
- Insert the qualified replacement and wait for the system to discover it.
- Choose the pool’s replace-disk action, select the new disk, review the warning and confirm. The force option destroys data on the selected replacement disk; never use it on a disk containing needed data.
- Watch the pool’s resilver progress and event log until it reports completion and the pool returns to an online or healthy state.
TrueNAS documentation dated March 2, 2026, says to replace a failed disk as soon as possible “to prevent further redundancy loss or eventual data loss.” It also states the replacement must be the same or greater capacity as the failed disk.
Do these 3 things before closing this tab:
1Repair Windows errors before they cause bigger problems2Scan for outdated or missing drivers - takes under a minute3Clear out junk files and repair common Windows errorsQNAP systems
- Open the storage or RAID management view and verify the failed disk’s bay and serial number.
- Check that the remaining disks and RAID type still meet the documented recovery condition; QNAP supports recovery when failed-disk count remains within that type’s tolerance.
- Replace the physical disk using the enclosure’s hot-swap procedure or its shutdown instructions.
- Assign the new disk to the affected RAID set. On some QNAP workflows, a replacement must first be assigned as a spare before rebuilding starts automatically.
- Confirm that the RAID status changes to rebuilding, then leave the NAS powered and stable until the process completes.
If the rebuild does not start, do not repeatedly remove and insert disks. Capture the status and logs and contact vendor support. QNAP guidance says to replace faulty drives and contact support when the process does not recover the data.
Synology systems
- Open Storage Manager and identify the storage pool, drive bay and serial number shown in the alert.
- Use the Replace Drive feature for the affected pool when the interface offers it. This workflow is intended to prevent the storage pool from remaining degraded while a drive issue is handled.
- Insert the compatible replacement only after confirming the selected bay and reviewing the capacity warning.
- Approve the replacement and monitor the repair or resync task from Storage Manager until the pool reports healthy.
Labels and menu names vary by DSM version and enclosure model. If the interface offers no replacement action, stop rather than selecting an unrelated repair or initialize command.
Rank #4
- Dual Converters, Infinite Potential：Includes 2× USB C male to USB A female adapters and 2× USB A male to USB C female adapters. Perfect for a wide range of uses—tablets with Bluetooth keyboards, expand USB ports on macbook, and more. Two different converters for all your daily needs
- Next-Level 10Gbps & 3A Charging: No more slow 480Mbps, this usb to usb c adapter has a transfer speed of up to 10Gbps, allowing you to do more transferring in less time. This usb adapter fits both USB A and USB C charger, supporting up to 3A fast charging
- Upgraded Exquisite Craftsmanship: With an aluminum alloy housing and metal connector, the usbc to usb adapter is extremely durable and sturdy. Rigorously tested to withstand more than 10,000 times of plugging and unplugging, ensuring long-lasting performance
- Broad Compatible: The usb c to usb adapter widely supports all USB C/ USB A devices like laptops, tablets, cellphones, car chargers, and phone chargers. Such as compatible with MacBook Pro/Air 2023/2022, Thunderbolt 4/3 Devices,Apple MagSafe Watch 9/8/7/SE/Ultra, iPad Pro 2022/2021, Samsung Galaxy S23/S20/S10, and iPhone 17/16/15 Pro. Plug and play
- Please Note: To reach 10Gbps speed, keep the cable under 3.3 ft. For USB A Male to USB C adapters, try flipping the USB C connector. USB C Male to USB A adapters support bidirectional 10Gbps transfer within 3.3 ft
Manage the rebuild or resilver
A rebuild reads surviving members and reconstructs missing data on the new disk. It can take substantial time, especially with large disks or a busy pool. During this window the array remains vulnerable, so keep the NAS powered, avoid unnecessary applications and do not change RAID settings.
- Ensure stable power; use a UPS where appropriate and do not reboot for routine maintenance.
- Keep cooling and ventilation normal. A replacement disk running hot can generate new errors during the most demanding phase.
- Allow the NAS to throttle the process if that is its normal behavior; maximizing speed at the expense of user workload can increase error risk.
- Check progress periodically, but do not cancel and restart a healthy resilver because the percentage appears slow.
- Read new alerts immediately. A second member showing errors changes the recovery decision.
Do not interpret a temporary performance drop as proof that the rebuild is stuck. Escalate when progress stops for an extended period accompanied by errors, the task repeatedly restarts, or the pool changes to read-only or offline.
PC Slower Than It Used to Be?
A free scan shows the junk files, broken settings and background clutter dragging Windows down - then fixes them in one click.Free scan · Windows 10 & 11Outdated Drivers Are Slowing You Down
One free scan finds every outdated or missing driver and matches the right update for your exact hardware.Free scan · exact hardware matchVerify the pool after completion
- Wait for the status to show healthy, online or the platform’s equivalent, with no pending replacement or resilver task.
- Review alerts for checksum, read, write, link or temperature errors on every member, not just the new disk.
- Run the platform’s consistency check or scrub when the pool is stable and the vendor recommends it. A scrub can find latent checksum problems but adds read workload, so do not start one while the pool is still rebuilding.
- Open representative files from each important share and perform a small restore from the independent backup.
- Restart normal backup schedules and confirm that the next backup completes and is restorable.
- Update your inventory with the replacement model, capacity, serial number, installation date and warranty details.
When to stop and escalate
Stop making changes and contact the NAS vendor or a qualified data-recovery professional if any of these conditions occurs:
Best Value
- 5-in-1 Connectivity: Equipped with a 4K HDMI port, a 5 Gbps USB-C data port, two 5 Gbps USB-A ports, and a USB C 100W PD-IN port. Note: The USB C 100W PD-IN port supports only charging and does not support data transfer devices such as headphones or speakers.
- Powerful Pass-Through Charging: Supports up to 85W pass-through charging so you can power up your laptop while you use the hub. Note: Pass-through charging requires a charger (not included). Note: To achieve full power for iPad, we recommend using a 45W wall charger.
- Transfer Files in Seconds: Move files to and from your laptop at speeds of up to 5 Gbps via the USB-C and USB-A data ports. Note: The USB C 5Gbps Data port does not support video output.
- HD Display: Connect to the HDMI port to stream or mirror content to an external monitor in resolutions of up to 4K@30Hz. Note: The USB-C ports do not support video output.
- What You Get: Anker 332 USB-C Hub (5-in-1), welcome guide, our worry-free 18-month warranty, and friendly customer service.
- The pool is offline, inaccessible or read-only.
- A second disk begins reporting errors before the first rebuild completes.
- The NAS cannot identify an eligible replacement or repeatedly rejects a disk that meets the published requirements.
- The rebuild or resilver fails, loops, disappears from the interface or produces escalating read errors.
- You are uncertain which physical disk matches the failed serial number.
- No independent backup exists and the data is irreplaceable.
Do not accept a forced wipe, pool recreation or “initialize” prompt as a routine fix. Those actions can destroy the only remaining copy. Preserve logs, screenshots, disk serial numbers and the exact sequence of alerts for support.
Common mistakes and their safer alternatives
| Mistake | Safer alternative |
|---|---|
| Pulling a disk because its bay light changed color. | Match the alert to the disk serial number and follow the platform’s offline step. |
| Installing a smaller disk because its advertised capacity looks close. | Use a replacement at least as large as required and check the platform’s exact capacity rule. |
| Using a desktop disk with no NAS compatibility check. | Choose a NAS-rated model and verify interface, sector format and vendor support. |
| Running heavy workloads during resilver. | Pause avoidable jobs and maintain stable power and cooling. |
| Forcing a replacement on a disk that contains data. | Confirm the disk is expendable; force options can erase it. |
| Assuming RAID0 can be rebuilt. | Restore the recreated pool from an independent backup. |
Practical decision checklist
- Have you recorded the pool name, bay, serial number and exact status?
- Can you open files from a separate, current backup?
- Does the RAID type still have enough fault tolerance for one more replacement?
- Is the replacement NAS-rated, supported, correctly sized and compatible with the interface and sector format?
- Have you identified the platform-specific offline, replace and rebuild commands?
- Can the NAS remain powered, cool and lightly loaded through the resilver?
- Will you verify health, run an appropriate consistency check and test a restore afterward?
Frequently Asked Questions
Can I keep using a degraded NAS while waiting for a replacement drive?
Only for essential, low-intensity access while you arrange recovery. Every additional disk error or heavy write increases exposure, so verify backups, pause avoidable jobs and replace the member promptly.
Does the replacement drive have to be the same brand as the failed one?
Not necessarily. The decisive checks are the NAS vendor’s compatibility status, required capacity, interface, sector format, physical fit and workload suitability. Follow any model-specific restriction shown by your platform.
Why did the NAS reject a drive that has the advertised capacity?
Usable capacity can be slightly lower than the failed member, and the platform may enforce exact size, sector-format or interface requirements. Compare the drive’s reported capacity and format with the NAS requirement rather than its retail label.
What should I do if another disk reports errors during resilver?
Stop nonessential activity and do not cancel or restart tasks blindly. Preserve logs and contact vendor support or a professional recovery service because the array may be beyond routine fault tolerance.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
