problems with VSS WRITERS for backups

Sometimes you are not able to backup the exchange databases because you get an error regarding to the writter, here you have the information how to fix it.

Open a command prompt as an admin

To see what writer is failing please type:
vssadmin list writers

Open a command prompt as an admin and write the follow line:
 NET STOP MSExchangeRepl

Once the service is stopped:
NET Start MSExchangeRepl

if its  Microsoft Exchange Writer:
net stop MSExchangeIS
net stop VSS
net stop MSExchangeRepl
net start MSExchangeIS
net start VSS
net start MSExchangeRepl

And voila, tray again with your backup script and should work.