Event Service, Sync Service and/or Pluginhost Service start, but then stop again after a short period

PROBLEM
You are finding that the Event Service, Sync Service and/or Pluginhost Service start, but then stop again after a short period

CAUSE
There are a few reasons for this, but by far the most common is as follows.
When an update or re-apply schema is run, a "flag" is set in the database to let other parts of the system know that the server is under maintenance.
When these services start, they check this flag and find that the server is in this state and will then stop themselves to allow the maintenance to complete.
To confirm that this is the case, perform the following steps

1. Check c:\kaseya\logs\services\XXXXX.log (where XXXXX is the name of the service that has failed), for example: KaseyaPluginHostServer.exe.log

2. Starting at the bottom, read up and look for

18/02/2015 17:08:59, INFO, "siteParams.messageSysStatus set to 1. Shutting Down.", "NULL", "NULL"

This "set to 1" is the flag that means that the server is under maintenance.

WORKAROUND / RESOLUTION

If you see the message above in the log, then take the following steps

1. Log in to the Windows Desktop of the kaseya server
2. click start -> Reinstall Database Schema
3. Watch this and wait for completion

If the process completes, you will be returned to the log in page. This successful completion of the re-apply schema will have set the flag to "ready" in the database and the services will now start and stay started.

ADDITIONAL INFORMATION
If you see any errors when running the re-apply schema, let us know.
Raise a ticket at https://helpdesk.kaseya.com. Include a screenshot of the error that you see and mention that you have looked at this KB article.