After upgrading to ver 16, I have been having problems with attaching a document/photo to either a product or to a contact / third party.
The system allows me to upload the photo / document but when I try to click on the link, it hyperlinks to a blank window with " ErrorFileDoesNotExists: 22/4DAC0313.jpg " at the top of it. When I click back to the previous screen, a warning displays in the upper right " A file with this name already exists. "
I am using Ubuntu 20.04.05 as the server with Firefox as the browser.
Run find -name 4DAC0313.jpg in your Dolibarr installation directory to see where the file was stored after upload, and how the path differs from the error message. Then maybe you can figure it out what happened.