How long does Uninstaller retain files and keys in trydelete.dat file?

[Brown Sugar]

I've often received a message after uninstalling a program which states that some files or keys couldn't be deleted, and Uninstaller will try again.   Exactly when does it try again and how long are these items retained in the trydelete.dat file?   I still see items in the file from several uninstalled programs ago.

[Admin]

It tries again every time you open the program (ZU) and keeps trying until it succeeds...

[soyabeaner]

I've noticed that in most cases when that message pops up, there is/are certain file(s) or registry entries being currently used by - none other than ZU itself , which make sense if you had it running all the way through from installation to uninstallation of an application.  In other cases, I find that ZU can remove things that it otherwise can't while in Safe Mode.  And in rare cases with complicated registry keys, it simply can't delete it at all.

[Brown Sugar]

It tries again every time you open the program (ZU) and keeps trying until it succeeds...

What if those files or keys no longer exist because the user may have subsequently deleted them manually, or a registry cleaner deleted several? 

In other words, at what point should be we edit the trydelete.dat file and remove references to programs that were deleted months ago?

[Admin]

If the file/registry entry doesn't exist it should automatically be removed from the 'trydelete' file...