I am on Windows, but some save discussions that may help
Mac and Root User http://forums.adobe.com/thread/879931
Troubleshooting guide for Mac freeze
Thanks for the suggestion but none of those work nor do they apply to my situation.
When you say "I try importing it with the shortcut and using the menu," are you referring to File>Import (CMD+I)? If so, have you also tried bringing the clips in through Media Browser or simply dragging the file from Finder to the Project panel?
One thing to double-check is whether you have something typed in Project panel's search/filter box [upper left corner of the panel]. If you do, then a newly imported clip will not show up if it doesn't match the filter. That seems unlikely since you've apparently been having this problem for a while. In CC, the search field gets cleared each time you close the app, but I don't have 5.5 handy to check in that version.
Yes I tried the File>Import (CMD+I) and dragging it in, which did not work.
But browsing it through the Media Browser which actually works, so thank you!!
Would there be a specific reason why dragging it in from the Finder menu doesn't work anymore?. My project panel does not have a search function aside from the Help menu.