Browser & Operating System (e.g. Firefox/Mac OSX): Firefox 5 and 6 / Win 7 Copy and paste any error messages: "A server error occurred. Please press 'Reload' in your browser." Describe the steps you took that produced this error: I've been encountering this error several times a day. I'll open up the spreadsheet, edit a cell or comment and receive this error. Sometimes it will happen when it's the first time editing the sheet that day, or sometimes after I've been using it for the last coupld of hours without any problem - there doesn't seem to be a pattern to when it happens. The data that was entered will be gone, If I refresh sometimes it will then work again without problems and sometimes it doesn't fix it and when I type the data again, it will produce the same error. I don't have multiple instances of the sheet open. This error has been reported by many people in the Google forums over the last 4 months, but Google are not responding. I've been forced to use Google Chome for viewing google docs and Firefox for everything else - I hope there is something Firefox can do!