Thunderbird Desktop 157.0, released September 30, 2026, lists fixes for a status bar that could keep running and drive CPU usage to 100% after activity ended, two OpenPGP key-handling problems, and several IMAP failures. Mozilla’s notes describe the symptoms but do not identify their code-level causes or report independent test results. Version 157.0.1 followed on October 1 with a separate EWS/Graph crash fix.
What Thunderbird 157.0 fixes
Mozilla’s Thunderbird 157.0 release notes list the CPU, OpenPGP, and IMAP items below under “What’s Fixed.” They are specific reported defects, not evidence that every Thunderbird user encountered them.
| # | Preview | Product | Price | |
|---|---|---|---|---|
| 1 |
|
Thunderbird | $3.99 | Buy on Amazon |
| 2 |
|
Thunderbirds and Flying Dragons: Evidence that Giant Birds and Pterosaurs Lived Recently | $12.95 | Buy on Amazon |
| 3 |
|
Thunderbird | $6.99 | Buy on Amazon |
| 4 |
|
Thunderbird Ranch | $14.99 | Buy on Amazon |
| 5 |
|
Thunderbird (Miriam Black Book 4) | $8.99 | Buy on Amazon |
Status bar and CPU usage
The notes say the status bar could remain active after activity ended and cause 100% CPU usage. They do not identify a platform, frequency, reproduction steps, or workaround for this particular defect. The 100% figure describes the reported symptom; it is not a prevalence statistic or a benchmark.
OpenPGP keys and encryption
Two distinct OpenPGP problems are listed: key discovery could fail to find a replacement after a key was revoked, and valid RSA OpenPGP keys could be rejected, preventing encryption. Mozilla does not specify algorithmic details or which key configurations were affected.
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 & 11Crashes, No Sound, or Screen Glitches?
Random freezes, missing sound and display glitches usually trace back to one bad driver. Find and replace yours safely.Free scan · under a minute#1 Best Overall
IMAP message saving, setup, and moves
- Sent messages: Messages could silently fail to save to the Sent folder.
- Account setup: Thunderbird could hang while waiting for the IMAP server greeting during setup.
- Moving messages: Pending moves within the same account could make messages disappear.
The notes do not name affected IMAP server vendors or indicate that all users or servers were affected.
How 157.0 differs from 157.0.1
Thunderbird 157.0.1 was released October 1, 2026. Its release notes list a crash fix involving EWS/Graph message handling and relative URL fragments. That is a separate follow-up fix, not an additional CPU, OpenPGP, or IMAP item in the reviewed notes.
Other changes in the 157.0 release
Not every item in the 157.0 notes is described as a fix. The release also includes optional manual IMAP/POP configuration ports, removes bundled RNP command-line utilities, and changes how remote content can be viewed in OpenPGP messages encrypted with integrity protection. These are separate release changes and should not be confused with the defect fixes above.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.What the release notes do—and do not—establish
The official notes document the symptoms and say they were fixed in 157.0; they do not explain the implementation-level causes, quantify affected users, provide a server-by-server compatibility matrix, or publish independent verification. A separate historical Mozilla Bugzilla report, bug 1973621, discusses a status-bar-associated high-CPU symptom and includes a reporter’s observation about disabling the status bar. It is contextual background, not proof of the cause or fix in 157.0, so disabling the status bar should not be treated as Mozilla’s documented solution for this release-note issue.
Quick Recap
Best Value
Rank #4
Rank #3
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.
