If you double-click on that icon, the CISM user interface will open up (if it doesn't, check this article).  From there you can cancel syncing, exit CISM, do a full sync (which you never should have to do), and start up normal syncing if it had been canceled by a user.  If CISM is currently syncing as it should, you will be able to see the last time a sync occurred and the next time a sync will occur (circled in red below).  (Note that depending on which version of CISM you are currently on, your screen may look slightly different than this.)