Out of all of the problems I’ve had, this one has been the most stubborn.
When I first installed Catalina, it seemed to work mostly fine except for one thing: Siri wouldn’t open. It would try over and over, generating thousands of crash reports if I left it long enough, all saying the same thing:
Termination Reason: DYLD, [0x4] Symbol Missing Dyld Error Message: symbol '_OBJC_CLASS_$_SiriUIDismissalOptions' not found, expected in '/System/Library/PrivateFrameworks/SiriUI.framework/Versions/A/SiriUI', needed by '/System/Library/CoreServices/Siri.app/Contents/MacOS/Siri'
I first tried to reinstall macOS, but to no avail.
Some googling of the issue told me that it was a dependency issue - but I can’t find anyone else with a similar issue that didn’t fix it by reinstalling.
I reinstalled again. Nothing. I tried replacing the file SiriUI it wanted a symbol from with a known working version from Mojave from a time machine backup. That still didn’t work.
How can I fix this, when neither a reinstall or known working file did? Is there any way to add the symbol to the file, or make it visible to the Siri app if it’s already there?