Report Error 606411740

Heidelberry

I had typed in an ISBN as an identifier to add a book to my list, it looked like it was saving the information (the gray box blinked on then off), and then it disappeared and was as if nothing happened. When I repeated the procedure it was normal.

adamsmith

If it works on a second attempt, don't worry about it. Likely a glitch in the connection to the database (worldcat) where Zotero looks those up.
As a general rule, error reports are especially relevant and appreciated where you can consistently replicate the error and provide steps to replicate.