There is no word yet on what we can expect from this release, since it is a alpha release I would not advise to make the change immediately from Thunderbird 2 to Thunderbird 3. Word is that not all plugins and add-ons are working in Thunderbird 3. If you cannot wait to make the switch make sure you backup all your data before doing so.

I will wait until a final version of Thunderbird 3 has been posted or a portable version of it. I do not want to risk losing all my mails even if I have a backup.

One of the official sites states the following:

In order to elicit feedback on new feature ideas, and get early and frequent feedback from the tester community, we will be releasing several alpha and beta releases of Thunderbird.

These releases are not for production use, but for developers and testers to give us early feedback. To emphasize this point, these alpha releases are called Shredder — they do not represent the final state of any Thunderbird release, can contain significant bugs, and should be handled with appropriate care

A link to the release notes was posted on the same page:

Shredder Alpha 1 is built on top of the Gecko 1.9 platform, which has been under development for the past 33 months. Building on the previous release, Gecko 1.9 has more than 10,000 updates including some major re-architecting to provide improved performance, stability, rendering correctness, and code simplification and sustainability.

The main goals of this release is to find out about possible problems caused by the changes in the underlying platform. While much has changed in the underlying code, there are few new features in this release. Notable changes include:

• The new Add-ons Manager (Tools > Add-ons) can now be used to download and install a Thunderbird customization from the hundreds of Add-ons available from our community add-ons website. When you first open the Add-ons Manager, a list of recommended Add-ons is shown. Note that few add-ons are compatible with this early alpha at the time of release, as add-on developers need to upgrade them.)
• The address book can now read data from Mac OS X’s system Address Book, but that feature is currently disabled by default. To enable it, see this blog entry
• New Crash Reporter (Breakpad) to report crashes in Thunderbird.
• Searching bodies of messages no longer produces as many false positives and has become more accurate in some multilingual situations.
• Improvements to our JavaScript engine have resulted in continued improvements in performance.
• On the Mac, Thunderbird is now a native Cocoa application.
• There is a version of the DOM Inspector that works for Shredder Alpha 1, available from Mozilla Add-ons.
• There is a version of the Venkman debugger that works for Shredder Alpha 1.

The Rumbling Edge reports 850 changes in Thunderbird 3.0 alpha 1.

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One solution would be to downgrade Thunderbird 1.5.0.8 to a prior version which should fix this immediately. A better solution would be to download a nightly build of thunderbird and use that. The bug was fixed and all coming nightly builds should contain the bug fix as well. This nightly build for example contains the fix.

Thunderbird 1.5.0.9 which will contain the fix will most likely be released sometime in December which means the only way to fix this bug now is to either downgrade or install a nightly build.

You will have to do the following no matter if you downgrade or install a nightly build:

• Backup your Thunderbird profile folder which is located C:\Documents and Settings\your username\Application Data\Thunderbird\Profiles\random.default
• Uninstall Thunderbird.
• Go to the Thunderbird profile folder and delete every msf file. Don’t worry,Thunderbird will rebuild them once you click on such a folder in Thunderbird.
• Install Thunderbird 1.5.0.7 or the nightly build

The missing mail should appear. Everything seems to have reverted back to normal for me using the above nightly build. Let me know if you encounter errors or if this method is not working for you.

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