The solution is to purge comstore from APISERVER log settings and keep only the last 10.
1- On Domain or Enterprise Manager, copy the attached file clean_apiserver.dms in a temp directory (eg: c:\temp)
2- Open a Command Prompt with Administrator rights and execute this :
cd /D c:\temp
start /wait dmscript.exe clean_apiserver.dms
This command could take 2 or 3 minutes
It generates a log clean_apiserver.log under DSM\logs
3- After a while (15 minutes or more) the size of file DSM\Agent\CCNF\comstore.enc should decrease around 4 MBytes