Sometimes when you publish a new menu item, and everything seems to be OK, when you try to access the new menu item you just created you hit the wall: instead of the intended content you'll see the following error:

Even more confusing can be the situation when a link which used to work behaves this way. The target content item is published, access rights are set to Public, and you still got this message! What can be wrong here?

You may already seen this annoying message instead of your Joomla site:

This site is temporarily unavailable.
Please notify the System Administrator.

And you are virtually clueless what to do about, and even the smallest bit of info on what happened can be a lifesaver.

Your Joomla site is hosted on 1&1? Great! ... Or not so great? Yea, I know the feeling, I had that experience too. All worked just fine (almost) until I decided to kick in the SEF engine, and use the .htaccess redirect, as I suggested elsewhere. And the disaster stroked...

It is an error which drive me crazy couple of times. It's easy to fix - but hard to detect why happening. I didn't see any good explanation which fits to each single situation I needed to handle it. There are couple of popular theories on what causes the "jtablesession::Store Failed - DB function failed with error" type of errors, but sincerely  I can not confirm any of them:

• Flooding (Check your http access logs for access IP’s, and your PHP error logs). Solution: Try dropping the time out down temporally to a lower value, to see if the sessions clear or not.
• SEF If your site has a lot of visitors table jos_session can accumulate substantial overhead. And if you use default SEF, some 404 pages can make some bots to enter into loop, and those bots gives you a huge session overhead.
• Site statistics from within Joomla. Enabling statistics through your site configuration just adds extra MySQL queries and increases server loads.

The WYSIWYG editors are great additions to the Joomla, and we have lots of them around. They make a webmaster from casual user and can speed up the work of pros. But, sometimes, you find that you cannot enter text into the HTML editor, or click on the HTML editor's toolbar buttons - you are locked out of editing your content!

What can be more annoying as being unable to edit your own site?

Do you are an early adopter and you upgraded to Joomla 1.0.13? And you have Community Builder, VirtueMart or SMF Bridge...and you cant' login right now, and/or your users are complaining about the same problem. We're sorry for you... Do you have a backup? Then is simple, restore the Joomla 1.0.12 files, overwriting the actual files with those from the official distribution package and restore the jos_users or similar (or at least the passwords column from that).

Do you have backup, don't you? No??? Ouch... humm, then the job is a bit harder, but can be done!

So, still you can do the file restore? Good, do it. Then read below!