I haven't heard of this one before. When I search that phrase, I only get 8 results, which is pretty unusual.

https://www.google.com/search?q=%22The+request+contains+a+U...

Does this affect a lot of sites, or just one particular site?

Are you following a link in search results or from another source?

Edit: fixed search link

It happen when attempting to open a link on a Facebook posting. It affects a lot of different sites. If I copy the link and try to open with a different browser, many times it does open there.

Hmm, could you post a few of these too-long addresses, assuming they aren't too personal? I'm not sure whether the problem is something Facebook adds (tracking code) or the original URLs.

This issue can be caused by corrupted cookies.

Clear the cache and remove cookies only from websites that cause problems.

"Clear the Cache":

• Firefox/Tools > Options > Advanced > Network > Cached Web Content: "Clear Now"

"Remove Cookies" from sites causing problems:

• Firefox/Tools > Options > Privacy > "Use custom settings for history" > Cookies: "Show Cookies"

Well, I may have accidentally fixed the problem. In attempting to open the offending links, things seem to be working. Thanks for your responses. If the problem surfaces again, I'll be back. Happy New Year!