How to change the temp location for the OAB Generation process on Exchange 2007 sp2 and Exchange 2010
Dave Goldman blogged how to change the OAB Generation Temp generation folder to a different location.
In Exchange 2007 SP2 we added a registry key called OALGEN_REG_V4_ALT_TEMP_FILES_LOCATION which will allow you to change the temporary storage location for the OAB Version 4 temporary files. This registry key will *ONLY* work for OAB Version 4. OAB versions 2 and 3's temporary files will still go to the %temp% directory. If this registry key is not present on the OAB's generating system we will revert back to the %temp% directory.
Being that OAB Version 4 is generated slightly different and uses different compression algorithms we can allow for a larger number of users far exceeded what we could generate on legacy systems.