This error message appears when I try to connect to a server recently. When the game automaticly reconnect the same thing happened again & again. I restarted the game and then Windows but still got this. Most attempts ended up with "JOOS - SET" but a few were successful.

I don't remember editing/changing any part of LFS except some DDS files. What should I do ?

Hi, is this whilst trying to join one server, or is it same for multiple servers?
If single what are the cars that are enabled?

*Assumption*
If its a single server someone might be using an unsupported set and you're getting JOOS'd?

Lets say someone is using R1s (or was it R4s; they were available in one of the test patches) for the UFR (and XFR?) and driving on a server when you connect: Either him or you will get JOOS and disconnect.

Or maybe its something else altogether...

A lot of servers, different combos.

The only server I successfully connected today was a XFG/XRG@BL1.

I'm using Z28.

Are all cars/tracks working in Singleplayer? Do you have big ping for servers?

Everything is right in SP. My ping is normal.

Tried reinstalling?
Warning: Make a backup of all skins and setups before uninstalling or that all will be deleted.

Reinstalled LFS and everything is fine now. Thanks.

I still wonder what caused the error ...

No problem. It can happen, that some of software is damaged and it gaves you errors. Or you was missing some files.