Can't open Adobe Acrobat file on external drive

[amieg73352143]

I can no longer open Adobe on my external drive.  I get a pop up that says file can not be found. see below.  I can drag the file off the external drive and drop it on my desktop and it opens fine.  

[moderator corrected the subject, was "Can't open Adobe on external drive"]

[Test Screen Name]

Is this a secure disk? is it a WD passport disk? Mac or Windows?

[amieg73352143]

I am not sure what a secure disk or WD passport disk are.  The external hard drive is a Bufflo TeraStation if that helps.  I am using windows.  It is a laptop and wireless.  All the others are computers and are hard wired.  I had no issues with this until recently 

[Abambo]

Can you access the file via Windows Explorer? Copy or renaming, for example?

(FYI: google WD Passport for information on this external disk device)

[amieg73352143]

I can access Windows Explorer, but still get the error, thisfile can not be found.   I can access all files on the hard drive except Adobe files.  

[Abambo]

I did ask you to access the file via Windows Explorer! Do an operation like copy the PDF file and report back. Do only this and report back.

[amieg73352143]

Sorry, I am not great when there are issuse on the computer.

I can copy or drag the file to my desktop