Thank you all.
I just reinstalled my whole operating system (win7) and Pro Tools (12.7) - it seems to be working fine for now.
In case anyone else experienced similar problems, below I am pasting the suggested solutions I got from Avid Customer Care (but haven't checked them myself, since I just went straight for "format C"
)
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1. Move all AAX plugins to the unused folder, then test playback, import, etc.
2. Import session data to a new blank session
To move all plugins to an unused folder, you may just simply go to "C:\Program Files\Common Files\Avid\Audio\", and rename the "Plug-Ins" folder to "Plug-Ins (Unused)". After this, restart Pro Tools and open the session you are working on.
If you are able to work on the session with minimal to no issues, start copying the AAX plugins one-by-one from the "Plug-Ins (Unused)" to the "Plug-Ins" folder that Pro Tools should've automatically generated. If the Error 6 comes up again, check which plugin was last copied then move that back to the "Plug-Ins (Unused)" folder. Continue doing this until all plugins are back to the proper folder.
Meanwhile, if you still encountered a problem, even after moving all plugins to a different folder, try importing the Pro Tools session to a new blank session.
To start you will need to:
1. Create a new blank session with the same parameters as your existing session (please save the new session on a hard drive other than the hard drive where the possibly corrupted session is saved)
2. Go to "File > Import > Session Data"
3. Have the following options selected:
- Timecode Mapping Options: Maintain absolute timecode values
- Audio Media Options: Copy from source media
- Video Media Options: Copy from source media (if possible)
- Session Data Import:
--- Tempo/Meter Map
--- Key Signature / Chord Map
--- Markers/Memory Locations
--- Window Configurations
--- Mic PRE Settings
- Main Playlist Options: Import - Replace existing playlists
4. Click on a track on the list under "Tracks" and proceed with the import
If there are any errors, continue performing steps 2 to 4 on the next track after the one last selected. Do this to all the tracks listed, until you have most of your data imported to your new session.
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