Just re-opened a project from last October. No changes in system since last time in the project except for adding some Red Giant goodies.
At first, the project would not open without a Shift+ALT startup. Once open, it shows missing camera media on the timeline and in the bin.
When I go to relink or replace media, PPro responds the media is either damaged or an unsupported file type.
It's very ordinary 720P MP4 shot with a JVC 890. All media plays fine in VLC media player, which also reports normal metadata. The media has been added as an exact copy from the original SD card structure, and originally introduced into the project via Media Browser. I have written over the media from the backup copy, but get the same results.
Dell Precision T7600 (x2)
Win 7 64-bit
Adobe CC 2014 (as of 7/2015)
256GB SSD system drive
4 internal media drives RAID 5
Typically cutting short form from HD MP4 and P2 MXF.