"Service Error: Database Is Read-Only" Message while trying to attach PDF to article

I recently downloaded the new Endnote 8 from my university’s website, I opened my old library that was working on 7 on 8 and everything came up okay. It did flash a message saying something about being locked, but everything came up anyway when I bypassed the message. The only problem I am having so far is when trying to attach PDF’s to my articles. It will let me attach it, the save message will appear, and then after that a message comes up that reads “Service Error: Database Is Read-Only” and will not let me save the attachment. I am not sure what to do! I have a Mac as well if that helps with providing assistance. 

It sounds like you still have both EndNote X7 (as in 17) and X8 (as in 18) installed. If you had the library already open in X7 and tried to open it in X8, you would run into this issue. I would first restart the computer and then uninstall EndNote X7:


Thank you! This was exactly the issue.