This standard operation is required to keep the performance of the server at a good working level, otherwise the server performance will begin to degrade.It is a function of the server and not a ECS problem. By rebooting you clean out any cached files that may over time slow down the server.  Clear-Com also recommends that you delete out

• Any *.tmp files that may have been created on the server C:\windows\temp.Action: delete all *.tmp files  

• Any *.tmp files on the ECS client PC. Once a month from the command prompt>CD/d %TEMP%>DIRtmp*.tmp>DELtmp*.tmp

EHX uses the Windows temp folder.  All *.tmp files should be erased from the temp folder.  
The path to the temp folder is similar to "C:\Users\username\AppData\Local\Temp", or it can be found by running this command “echo %temp%” from a command prompt.  

see also FAQ : EHX displays message about not being able to access an EHX file from the temp folder.