exactly when (save as, save, export)? On saving existing .ai file does the error happen every single time? Not every. Sometimes program shows message (file error, cannot save - they may differ), sometimes it just crashes, leaving .tmp file in original file's directory. Sonetimes saves perfectly. One more thing: if i open .ai file's dir in Finder, click the file and after that deselect it, saving error sometimes disappears. Not sure about these cases, make not much tests on it. type of drive: SSD, external drive, google drive, dropbox ? A screenshot of your drive would help as yo may have chosen the AFPS drive formatting? Network drive. Also, unable to save EPS files on network drive, error -47. It all started after updating to High Sierra. Software version is CS6.
... View more