Wow, I just saw another post relating to this same root cause.

Try checking the ''Repository Migration Status''. My guess is that this project was upgraded from QC10 or 9.2, and it is not finished ''migration'' (converting) the project repository to QC11 format.

Sometimes it gets ''stuck'' at 99% and the problem is just a leftover file or folder int he project repository.

In site Admin, go to Tools / Repository Migration Status. Then, see if your project (and possibly others) does not say 100% migrated.

Try to Resume migrating and look at the message in the ''additional information'' box - It will have a path to a file with details about what is wrong.

Usually, there is a leftover folder or file in the project's repository folder.
It should only have a folder called ''ProjRep'' and a file ''DBID.xml'' in there. Don't delete other stuff unless it specifically complains in the migration log about it -- otherwise you could accidentally delete working repository artifacts that have not been migrated yet.

So... the two ''symptoms'' of failed repository migration due to upgrade from version earlier than QC11 are:

1) cannot copy project or generate QCP

2) Odd behavior in Tests tree when filtering or reporting.