alanrf
2
Like most products that update in a sensible fashion avast downloads mostly to the directory in Windows designated to hold temporary files.
avast rarely downloads the whole of the VPS files instead it downloads incremental updates and then integrates those updates into the VPS database within the avast program folder structure. The temporary files are then deleted.
Clearly a program update is more complex but follows a similar path, downloads to temporary files and the updating of the avast program files in the avast program folder. Typically avast program updates require a system restart and are dependent on information that will survive a system restart.
ShadowUser sounds like a relation of a product I use (now unfortunately owned by Symantec) called Goback. It provides similar features but (in normal use) it does not affect any changes across system restarts. It allows me to take my entire system disk(s) back to within about 10 seconds or so of any time in the last couple of weeks. It can also be run in a pure “sandbox” type mode or to simply restore the whole system to a set point in time on every restart. It does more too but I’m not here to sell the product. However, the basic principle is everything rolls forward consistently or everything is rolled back consistently - not a little bit of this and a little bit of that.
I would suggest that picking files/folders individually to be saved across a restart will certainly lead to inconsistencies and trouble one day. I hope that you have a full backup/imaging strategy to recover your system for when the day happens.