Why can't I delete a file?

When trying to clean up my files in Adobe Acrobat DC, I discovered that I cannot delete certain files. When I right click the file name, it sends me into an infinite holding pattern that eventually results in closing the non-responsive program.  I checked the security of the documents, and there are no "security" elements attached to the document that would prevent deleting. 

Any suggestions within Acrobat or otherwise would be appreciated.  The growing concern is that these are corrupted files and may be harmful to my drive.

THANKS!