| "AppData" is where user specific application data is supposed to be stored. "The Registry" is where application configuration is supposed to be stored. "ProgramData" is where application specific data is supposed to be stored. "Program Files" is where read-only application binaries and code is supposed to be stored. It really is a simple concept from a Windows perspective. What ruins everything is overzealous and/or ignorant programmers who don't take any pride in their work, or lack all respect for the users environment. For example; an .ini file should not be a thing in Windows. That is what the registry is for. But the programmer writes the code for Linux, half-ass ports it to Windows, and leaves the .ini file because his code is more important to him than the end-users operating system. There is nothing wrong with AppData permissions. The problem is with the users understanding of what it is for, and the developers understanding of how it should be used. |
Developers (including those inside Microsoft) don't give a damn about how Microsoft intends anything to work, and AppData has become a dumping ground of software installs to end-run IT departments. A lot of malware dumps into there but good luck limiting execution from that directory hierarchy because all your business-critical end user communication apps live there now too.
The functionality of roaming users profiles (i.e. registry settings "following" you to a different computer, which gives a really slick user experience when it works) was completely ruined by devs dumping piles of small files into "AppData\Roaming" (and completely not understanding that "AppData\Local" even exists, let alone what it's for).
In Windows 2000-land you could redirect AppData to a UNC path and mostly get around this behavior. That's not really "a thing" anymore because you've got apps like Microsoft Teams storing sizable databases in these locations and getting really, really cranky if network connectivity is interrupted.
Windows development betrays its legacy DOS parentage even for devs who never lived thru that era. There were no rules. There was no adult supervision. There was poor documentation of APIs so you just hacked something together that worked well-enough. Periodically Microsoft tries to start over (all the APIs w/ "2" at the end, et. al.) and the cycle repeats.