Problem viewing PDF files on read only USB drives.
I am distributing pdf files on USB drives that are locked for read only at the hardware level. Until about 6 months ago, I was able to do this with PDF files. Now, when I try to open a pdf file on a locked drive, I get an error that the file is corrupted. I can unlock the drive and then the file can be viewed without issue in Reader or Acrobat. I see this bug using two different manufacturers USB drives. It also reproduces using pdf/a files rather than standard pdf files. Marking the pdf file as read only doesn't help either. And as I mentioned, earlier versions of reader (up to about 6 months ago) work fine under these same conditions.
If you need any more information or hardware samples to test, please contact me!