We have been pushing the Outlook client for CRM2015 for a few months on new systems. We have also been pusing it on demand slowly to about 20% of our 2013 users. We started pushing out to the remaining clients but I'm now getting failures. 

Program failed (download failed - content mismatch)  10057

I did a LOT of searching on this and have done the following:

 - refreshed the package

 - rebuilt the package

 - Validated the package

 - there are no hidden files in the package

 - enable binary differential replication is not checked

 - used SCCM Client Center to Reset Policy (hard reset)

 - reinstalled the client on a few systems

I'm still getting the content mismatch error.

I dug into the CAS.log and found the following error:

[Failed to open file c:\windows\ccmcache\c\reportviewer\reportviewer.msi with error [32].

[HashFile - exclusive access check for the file failed.]

Other systems had the same type of error but with different files:  \sqlce\ssceruntime_x86-enu.msi, \sqlsystemclrtypes\sqlsysclrtypes_x86.msi, \muisetup_1033_i386.msi, \client.msi...

In the CAS log, multiple install attempts on the same system show the same error 32 each time but with different files within the package.  If it was with the same file, I'd pull it out and re-run it for troubleshooting... but it's not.

We have not seen this error yet on Win 8.1 systems... only on win 7.  I need some ideas of other things to look at. 

thanks

Have you excluded your AV from scanning the ccmcache folder?

Thanks Jason... I don't think it is excluded.  I have submitted a request to make that change and will let you know if it works.  Your thought makes sense... i'm going to see about changing the deployment in the short term so that it performs a reboot before starting the install.  That should release the AV hold.  thx

that did it. now i hope to never have this issue again. thanks!