CsiSrvExe.exe (0x1C40) process?

I'm doing a bit of troubleshooting regarding a user not receiving an email, I suspect it's either a list alert or a workflow. The logs turned up:

Process: CsiSrvExe.exe (0x1C40)
TID: 0x2462
Area: SharePoint Foundation
Category: Client File Access

ttidLogWssCellStgConcise [Url: http://intranet/file.xlsx ][User: domain\user123 ][User-agent: GUID={123456789}, OfficeBuildNumber=14.0.7137.5000 requestVersion=12][StreamSizes: Request=10678 bytes, Response=282 bytes][TotalRequestTime: 187msec][PartitionID: Default][Request: PutChanges **PFU Result=Success][cbOld=107395][cbNew=107385][cbOldFFM-C=5551][cbNewFFM-C=5565][cbOldFFM=17398][cbNewFFM=17398][Coalesce: Ran successfully in 172msec (ClientRequested, NonHotAwarePartition)]

Can anyone tell me what CsiSrvExe does? I found the following, which doesn't seem to relate to the issue, but if anyone thinks it might:

OneNote uses the Core Storage Infrastructure service to send user edits to the SharePoint server. This server stores the master copy of the notebook. The Core Storage Infrastructure service processes file writes by storing them in a hot table and then periodically flushing those writes to the actual file. Anyway, there was something seriously going wrong with this web service. http://bramnuyts.be/tag/csisrvexe-exe/

Thanks