Hi,
Windows 2008 R2 SP1 is not supported, other users have reported issues installing CRM 2011 with SP1 if you are planning doing a re-build.
However is listed for CRM 4, note that it is only supported for CRM 4 on rollup19.
RU10 was released August 10 and that list has been updated September 7, so RU10 does not introduces SP1 yet. However on an interesting note, CRM 2011 supports FIPS which should only run with SP1.
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