When I tried to upload an attachment, nothing would happen. I wouldn't even get an error message.
I was not able to upload e-mail attachments with Firefox or Chrome, and Internet Explorer wouldn't even open any websites.
The problem may be because you accidentally changed the internet settings for the whole computer somehow and did not realize it. This could have been done by several ways, including but not limited to, fooling around with the Internet Explorer settings.
I use Firefox regularly but I fixed this problem by opening Internet Explorer and doing these steps.
Tools -> Internet Options -> Advanced
When in the Advanced tab, did these two things
1) Click "Restore Advanced Settings"
2) Click Reset (and OK to all the message warnings)
After I did that, I was able to upload e-mail attachments on g-mail with Firefox, Chrome, and Internet Explorer.
If you're seeing error messages while uploading attachments, make sure you have Flash installed. Visit http://get.adobe.com/flashplayer/ to check for updates and download the latest version.
In addition, please make sure that Flash is not being blocked on your computer. If your computer's default browser is Internet Explorer, make sure that it's not in "offline mode."
Please note that this feature is not supported on Linux.
If you're using Flash 10, try these troubleshooting steps (note that you may not need to do all of the things listed below to fix the problem):
* Switch your attachment settings from 'Advanced attachment features' to 'Basic attachment features' (click Settings and select the General tab to change this setting). Save your changes and try to upload your attachment again.
* Try another browser.
* Disable your proxy.
* If you continue to have trouble after following these suggestions, report it here.