We have a number of 10.9-10.9.3 - Mavericks - machines installed throughout our facility. Much of the user content is pulled from shares stored on our Windows Server 2012 fileservers with deduplication enabled. I have found that files newly written or unoptimized are able to be accessed without issue - read, written, modified, etc. Once the file gets optomized/deduplicated and Windows adds the P & L attributes - sparse and symlink - the Macs running Mavericks begin to have access issues. Once the files get deduplicated, users begin receiving read access errors when copying files (see error1 below). This happens when copying to folders within the current folder tree or copying somewhere to the local system. If you 'stop' the copy operation and retry a few more times, it may eventually work for the specific instance but fail again later. I am however, able to copy these files without issue via the terminal. Other systems running 10.7 do not experience the same issues and are able to access file server resources without issue. Many of the systems having issues are newer and thus not able to be downgraded to 10.8 or 10.7. I have tried finder replacements such as Pathfinder but the results are the same. I know this is at least similar to the issues many Mac users are already experiencing and posting about but I haven't seen it directly linked to deduplication and the attributes written by Windows server. Has anyone seen this issue? Have any solutions been found? Error 1: When copying files after the PL attributes have been set by deduplication. "One or more items can't be copied to "Foler" because you don't have permissions to read them. ******************************************' Via the system.log, I am also seeing the following error when accessing these deduplicated file shares. The reparse point tag listed below is "IO_REPARSE_TAG_DEDUP" Reported error: "smbfs_nget: filename.ext - unknown reparse point tag 0x80000013"