There are a few forums I frequent on a regular basis and I have auto login enabled.  Meaning I don't have to go through the process of logging in every time.  Places like here, SD.net, IMDB, Ebay and so on.

However, I'm now noticing that I have to enter the details in every time I visit these forums and would like to know what could be done to solve it.

Check your Privacy settings...

Tools->Options->Privacy

Check that the setting are such that your browser will accept cookies and third-party cookies from sites, and that they are set to keep until they expire.

I'm not sure if cookies count as private data, but that the next setting, so you should make sure that the box to clear private data when you close Firefox is not checked.

I don't think there are any other settings that affect this, but since I automatically kill cookies all the time and never allow any to live past the current session, I'm not the best to advise in detail.

There's nothing wrong with cookies as such, but when you examine the cookie pot, it's always full of silently added cookies that are used by spy-tracking programmes - it's not that most of them are a real problem, but I object to the info being taken without me having a say, and the cookies being replaced with new ones after I remover them.

That said, let me know if this was the cause or not, and I'll look a bit deeper if the login still doesn't persist.

All that was set as you said.  I blanked the "Remember what I enter in forms and search bar" button and rechecked it.  I'll see if it holds.

It's just that this is a bit of a minor annoyance.

That's a tad odd

Have you checked for browser dependency?

Does the same thing happen in IE?

I don't know if you have any anti-virus or firewall software installed, but this may be interfering with cookies. It's getting harder and harder to know what each of these is doing nowadays, ditto if you have any sort of spy-bot packages installed, but they'll kill cookies they don't like to, and sometimes need specific sites added to a "whitelist" in order to allows then to stay alive.

If you have any of these, then it's just a case of slogging through their setting and list to try and find out what they're doing.

Don't know if you are able to check cookies stored on your PC and interpret the contents. If you can, the prefix for the forum cookie is:   eblah

Strange thing is that this has just happened from today.

Odd.

May be obvious, and irrelevant, but worth thinking hard for a moment about any new software, updates, or changes that have been made elsewhere over the past week or so, just in case. Sometimes the most innocent little tweak somewhere can create a surprise elsewhere.

If it wasn't the end of the month, I'd have suggested a look at Windows itself. If you have the recommended setting to accept the Microsoft updates delivered automatically each month. these can produce the occasional odd side-effect if you forget these are happening, but this update is usually parachuted into you system in the early part of the month.

I can confirm that there have been no changes made to the forum that would have affected this, and the 10.3.6 upgrade was some time ago now, so unlikely that it has a bug.

Well I wasn't blaming Secret Scotland as it's happened to every forum I go to, so I knew the forum update wasn't to blame.