I am currently using the latest version of PS: 21.1.2 on a Macbook Pro 2018.
I cannot save my 2.69 GB document for some reason anymore. I initially opened the PSD file, made some edits in PS, then resaved it, and was given an error related to the document size, I believe. I have never received this error before. So when this happened, I then tried to save the file as a PSB since that file type supports large files. However, when I went to click "Save As" or "Save", photoshop literally did nothing and still is not doing anything... so I am not sure how to go about saving my file. I am not sure what to do or why it is doing this. All I want to do is save my file, close photoshop, and eject my external hard drive. I do not want to lose the work I made on the file. Also, I checked and I can not create new files on Photoshop either.
We are sorry about the experience with Photoshop while trying to save your work. Would you mind sharing macOS version you are using? Have you tried using the keyboard shortcut, Ctrl/Command + S to check if that helps? Are you able to access the export options like Export As or Save for Web if you go to File > Export?