This article describes the error and its resolution, which occurs when creating a VSS based backup:
Error: 'The number of WaitHandles must be less than or equal to 64'.
A VSS based backup (e.g., using Windows Backup) can fail with the warnings/errors listed below if the installation contains a high amount of Archive Stores:
Application Event Log Entry: Type: Warning
Event ID: 8229 A VSS writer has rejected an event with error "0x00000000, The operation completed successfully".
Changes that the writer made to the writer components while handling the event will not be available to the requester. Check the event log for related events from the application hosting the VSS Writer. VSS\DebugLogs\VssWriter.log reads:
2014-03-12,23:01:14,739,1,"#0000144C","#0000000C","error","VssWriter","error: Prepare for snapshot failed - The number of WaitHandles must be less than or equal to 64."
GFI Archiver build 2013111
To resolve the issue, upgrade to MARC2014 build 20140616 (attached in this article) or newer.