Recent list is stored in Registry at:
'Computer\HKEY_CURRENT_USER\Software\Scirra\Construct2\Recent File List'
If you are confident with working with the registry, you could have a look here and check.
It's possible that the registry settings maybe corrupt, in which case, removing C2, deleting the Scirra key branch (backup registry first!!!) and reinstalling may work, but I wouldn't recommend it if you not totally proficient in working with the Registry, as serious damage can be caused if you do something wrong.
I've check the registry, and I can't find the recent file list.
I try to deleting the Scirra key branch and reinstalling C2 ,but it still not work~