Can't attach files to Yahoo! Mail?

I have been having problems with Yahoo! Mail recently and it works fine except for one thing. I cannot attach a file to an email. I click the attach button, select a file, and Yahoo! Mail tries to upload it and fails. Every time no matter what file it is or what size it is. A search of the web found other people with this problem, but no solutions. However, I found a work-around that fixes it.

I've been using Yahoo! for years and have sent a zillion emails with attachments, so it crossed my mind that my mail account might be full. I can't see any usage indication in Yahoo! Mail, so I don't know whether it is full or not. I searched for old sent files with attachments and deleted them, freeing up some space. I still couldn't attach any files.

It crossed my mind that it could be the browser and I normally use Google Chrome. I fired up Internet Explorer, but it was no different and files could not be attached to emails. The problem seemed to be independent of the browser.

The Attach button in Yahoo! Mail is actually Flash. I uninstalled Flash ages ago partly because it isn't needed so much these days and partly because Chrome has Flash built in so you don't need to install it separately. It is also known to cause various problems too. Well, I am also using Windows 8 and Internet Explorer 10 has Flash built in too. So both Chrome and IE have Flash and neither browser would attach files to emails. Unlike normal Flash, you cannot upgrade the Flash plugin in these browsers because it is built in and you have to wait for a browser update.

The solution was to use Firefox. This is completely Flash-free because I've not installed Flash in Windows and it is not built into the browser. If you access Yahoo! Mail with it, the mail page detects that you don't have Flash and displays a regular non-Flash button. This attaches files to emails just fine.

So there you have it. If you can't attache files to Yahoo! Mail messages it is Flash and without Flash it is fine.