Problem with check in files

One of the users has checked out few SolidWorks files and when he tries to check them back in, error comes saying that the files are checked out on another computer. However, the computer and the user which is shown in the error is the same computer he has checked the files.

It's been about 2 weeks since he checked out files. Pls let me know how this can be solved.

SolidworksSolidworks Pdm enterprise Pdm