I learned the hard way.

Whenever you change *anything* with sh404SEF, it asks you if you want to clear the "cache" [and this is "recommended" for some obscure reason]. I assume, like most Joomla! stuff, it was an in memory cache or something else that probably needed to be cleared, and didn't harm anything. It's recommended so ....

So I cleared it. And then all hell broke lose.

It seems that the "cache" is actually the real, actual URLs list to the pages and not just a "performance based cache" (like xcache, fore example). And when you clear it, the system then has to regenerate each URL.

Any pages that have had their titles changed, or moved to a new category or was in other ways modified, generates a new *different*, url.

There went my "page #1" on Google for some of my search terms.

So I then spent the next 2-3 hours find the old urls, mapping them, then creating 301 redirects from the old URLs to the new ones. I'm still not done.

So, what I learned: once your site is live NEVER CLEAR THE CACHE - despite the fact that it "recommended" to do so. You'll lose ALL your SEF URLs.

Instead, make changes one URL at a time, if you have to, and use redirects (preferably 301s) when needed.

I'm interested in hearing other tips from people using SEF URLs.

hi there,
how did you do the 301 re-direct. i currently have a ranked page from my new joomla url, and so i would like the old Url to point to the newer url.