It seems like, with every new version of 10.6.x, GrowlMail gets disabled by Mail.app. Sure enough, this has happened again with 10.6.5 and Mail 4.4.
Rather than wait until someone posts a patch to get it working again, I figured I'd find out what needs to be done, and how to do it.
Thanks to Paul Kehrer's previous posts, which have been summarized in this previous hint, it is possible to fix this using a slightly different process. This method should continue to work for future revisions as well, at least with Snow Leopard.
GrowlMail ceases to function because it has a list of supported versions of Mail.app and the Message framework. Since Apple updates these apps and the version numbers change, GrowMail thinks it is no longer compatible.
BTW, whether it actually is compatible or not is not the topic here; this is just to allow it to run again -- whether it actually works is a different can of beans.
The first thing to do is to get the current UUID's for Mail.app and Message.framework by looking in their respective info.plist files:
defaults read /Applications/Mail.app/Contents/Info PluginCompatibilityUUID defaults read /System/Library/Frameworks/Message.framework/Resources/Info PluginCompatibilityUUID
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>CFBundleDevelopmentRegion</key> <string>English</string> <key>CFBundleExecutable</key> <string>GrowlMail</string> <key>CFBundleIconFile</key> <string>GrowlMail.icns</string> <key>CFBundleIdentifier</key> <string>com.growl.GrowlMail</string> <key>CFBundleInfoDictionaryVersion</key> <string>6.0</string> <key>CFBundlePackageType</key> <string>BNDL</string> <key>CFBundleShortVersionString</key> <string>1.2.1</string> <key>CFBundleSignature</key> <string>emal</string> <key>CFBundleVersion</key> <string>1.2.1</string> <key>NSPrincipalClass</key> <string>GrowlMail</string> <key>SupportedPluginCompatibilityUUIDs</key> <array> <string>B3F3FC72-315D-4323-BE85-7AB76090224D</string> <string>225E0A48-2CDB-44A6-8D99-A9BB8AF6BA04</string> <string>99BB3782-6C16-4C6F-B910-25ED1C1CB38B</string> <string>2610F061-32C6-4C6B-B90A-7A3102F9B9C8</string> <string>2F0CF6F9-35BA-4812-9CB2-155C0FDB9B0F</string> <string>0CB5F2A0-A173-4809-86E3-9317261F1745</string> <string>B842F7D0-4D81-4DDF-A672-129CA5B32D57</string> <string>E71BD599-351A-42C5-9B63-EA5C47F7CE8E</string> <string>BDD81F4D-6881-4A8D-94A7-E67410089EEB</string> <string>857A142A-AB81-4D99-BECC-D1B55A86D94E</string> </array> </dict> </plist>
$ defaults write ~/Library/Mail/Bundles/GrowlMail.mailbundle/Contents/Info Suppor tedPluginCompatibilityUUIDs -array-add "the_new_number"
Mac OS X Hints
http://hints.macworld.com/article.php?story=20100823103751355