Report an Issue is probably a better place to post this.
Several things that you can try to see if they make a difference.
Get a local copy of the file. Will it open?
You've indicated that you get a dialog asking for a missing file. If you open manage | External data sources, you should be able to find and remove that external data source reference and then this dialog will no longer appear. That is unlikely to fix your problem but does reduce the number of possible issues by one.
Try recovering a copy of your file, put the recovered copy up on the server unless recover does not recommend using the recovered copy and see if it has the same issue.
Things to keep in mind about Recover:
While Recover almost always detects and fully corrects any problems with your file...
- The recovered copy may behave differently even if recover reports "no problems found".
- Recover does not detect all problems
- Recover doesn't always fix all problems correctly
- Best Practice is to never put a recovered copy back into regular use or development. Instead, replace the damaged file with an undamaged back up copy if this is at all possible. You may have to save a clone of the back up copy and import all data from your recovered copy to get a working copy with the most up to date information possible.
And here's a knowledgebase article that you may find useful: What to do when your file is corrupt (KB5421).