I'm unable to download Apps or Update apps from Google Play Store. And i get these errors :- 1. if i'm trying to update i get Error 921 2. if i'm trying to download, it says, "unable to perform purchase" (and i'm just trying to download free app, not paid) 3. Tried uninstalling and rolling back to ver. 3.1.5 (as sme1 has mentioned this on xda forum), but then i get error -101. *Solutions Tried * ----> 1.tried the method of unmouting the shared storage as mentioned here... miuiandroid.com/community/threads/miui-rom-2-3-16-ics-gb-roms-uploaded.15733/page-14#post-113549 2. Clearing cache and data of Google Play/Market didnt help either. Any help appreciated.