I installed the KL Codec Pack 2.20 full version (tought it was time for an update, my mistake...)
And I noticed a rather annoying problem.
When opening a folder with several .ogm files in thumbnail view it will only load the thumbnail of the first movie and then Explorer.exe will crash:
Windows Explorer has encountered a problem and needs to close.
AppName: explorer.exe AppVer: 6.0.2800.1221 ModName: ole32.dll
ModVer: 5.1.2600.1263 Offset: 0001213e
My Google results only pointed to a problem with DivX 5.11 beta and Overlay Extended Mode being enabled, which is off by default.
Hope somebody can help...