Relevant Product: Signature Manager Office 365 Edition
You observe the following error in the Event Log:
This error is displayed when the number of temp files reaches a given number - e.g. ~65K.
There are a number of reasons why this can happen but generally, temp files simply tend to build up over time.
Temp files used by Signature Manager Office 365 Edition adopt the naming convention of: tmpXXXX.tmp. To resolve the error, delete these files from the following locations:
You may also find these temp files in your own %temp% directory.
Having deleted the files, access the Exclaimer console, make any minor change to the configuration and save changes - the error should not be shown in the event log.