When should I need to Fix Permissions?

[jean15paul]

So I'm trying to improve my understanding of all things Android Rooting related, and I have questions about the "Fix Permissions" functionality in TWRP/CWM/Rom Manager etc.

So I've done some searching and I think I have a basic understanding of what "Fix Permissions" does. It seems to make sure that the app.apk, app data, and app permissions all match up. I've read a few different articles/posts, but these are the most useful ones that I've found:
http://forums.androidcentral.com/ve...od-recovery-w-screen-captures.html#post690581
Fix permissions - CyanogenMod Wiki

What I haven't found is any good thorough infomation about when you should fix permissions. I've seen some people say that they arbitrarily try it if they are having problems (force closes, ROM not behaving properly, etc). I've seen some people say they do it after every flash. Other have said that it's not necessary after a full wipe, but they do it after every dirty flash.

So here are my questions:

• When does it make sense to fix permissions?
• Is there anytime that you shouldn't fix permissions?
• Similarly, is there any danger in fixing permissions, or is it always safe to do?
• From a technical standpoint, how does Fix Permissions know what data goes with what app?

Thanks everyone for the help

 

[2defmouze]

You shouldn't have to. It's a relic of an earlier time in custom ROM flashing. Some people still think you should or that it helps fix issues, but no. Lol.



Sent from my Nexus 4 using Tapatalk 2

 

[jean15paul]

You shouldn't have to. It's a relic of an earlier time in custom ROM flashing. Some people still think you should or that it helps fix issues, but no. Lol.



Sent from my Nexus 4 using Tapatalk 2

I must admit that I'm a little skeptical of that. Only because, when I dirty flashed the CM10 12/4 nightly over the CM10 11/24 nightly, I had an issue. My phone wouldn't recognize that headphones were plugged in and would still play out of the external speaker; also the external speaker volume couldn't be changed. I tried a bunch of stuff and nothing fixed it. Then I tried "Fix Permissions" (in TWRP), and it seemed to resolve the problem.

I'm not an expert, and it could have been something else, but that is was seemed to fix it.