Hi
Windows indexing, backup, update etc. and other applications such as antivirus tend to run their resource-intensive functions such as system scans at "quiet" times when the PC is not being used by the user, i.e. no mouse or keyboard activity. These are also often configured to run overnight.
If you run MFP overnight, at some stage you will almost certainly have a resource conflict with one of the above.
The suggestion here is to switch off as many of these automated resource-hungry tasks as you can, and run them manually if needed when MFP is not running.
Of course the best way is to have a dedicated machine for MFP only, which is stripped down of all un-needed applications and configured for no automated updates, scans etc. - or operate a VPS.