Unpredictable Server Browser behavior

NOTE: this will delete all servers in your favorites and in your history!

Exit from Steam first, then delete:

C:\Program Files\Steam\config\serverbrowser.vdf or C:\Valve\Steam\config\serverbrowser.vdf

Steam will re-create those files for you the next time you run.

NOTE: Steam will only save Server Favorites and History at the Steam ServerBrowser, not from within the game serverbrowser.

IE: If you are connecting to Servers from within the game ServerBrowser, it will not save the Servers to your favorites. If you connect to Servers from the main Steam Serverbrowser then they will save properly.

Update: It is very important that you make sure your Steam Rate is set properly, if you have very slow server updates then your rate is likely set wrong.

Router Problem

There are also a few routers with bad firmware that have overflow problems when there are too many servers. A symptom of this is where you refresh CS for example and always get 8000 servers and then it stops. These routers will also typically go offline for a minute or so when they overflow. The only solution for this is to get updated firmware for the router or replace the router.