Opus 13 pdf adn office documents access denied when loading from cloud

Hi there, since installing Opus 13.4 and still with 13.6, when I try to open a PDF and sometimes an Excel file that is on my Dropbox or Onedrive, I get an access denied error in Adobe, and in Excel- it just says the file is corrupt. I can open the files with Explorer. I have checked the Metaplugin settings and I think all is OK there- any suggestions? I ran Opus 12 and earlier versions for many years and this problem did not happen there.

Check your antivirus and any privacy/malware/ransomware protection tools, as they may block some processes from accessing documents.