Accounts & Sync missing

[vovalos]

Hello all. I have a Sony Ericsson Xperia Pro running Android 2.3.4. It's rooted and was working fine for months. I little while back (not sure exactly when), it stopped synchronizing the contacts & calendar.
Upon investigation I've observed the following:

• There is no "Accounts & Sync" menu option in the main phone settings menu anymore
• The "AccountAndSyncSettings.apk" is missing from /system/app/ folder
• If I go to Phonebook/settings/Accounts & Sync I get a message "The application Contacts (process com.sonyericsson.android.socialphonebook) has stopped unexpectedly. Please try again"

What I have tried:
1. Download the "AccountAndSyncSettings.apk" and try to install it using Apk installer. Fails saying "apk not installed" with no explanation.
2. Manually copy the AccountAndSyncSettings.apk to the system/app folder using Root Manager. I get a message that it's a read only folder.

Any thoughts on what I can do?

 

[SpookDroid]

If it shows as a read-only folder it sounds like you lost root at some point. You could always try to re-flash your current ROM (if you're using a custom one) or, in the worst case, do a factory reset.

 

[vovalos]

Thanks SpookDroid
I'm pretty sure that I didn't loose root, as my Uninstaller can still delete the preloaded apps (and give me a message "superuser permissions granted").
I'm not using a custom ROM (not sure if I should, but that's a separate question). Regarding the factory reset - I'm guessing I will need to root it again after (that should not be a problem), however I've also unlocked it from my carrier, will it re-lock? How would I do the reset if I decided to go that way? My software keeps asking me if I want to upgrade to android 4.smth , I don't want to do that, Android 2.3 is working out great for me so far, if I do a reset will it automatically upgrade?

Thanks

 

[SpookDroid]

If you do a factory reset it won't upgrade until you specifically tell it to. As for the unlock, it all depends on the method used. USUALLY you don't lose it, but I might be wrong. For that I'll let someone else chime in.

 

[vovalos]

Just to put an end to this thread. No factory reset didn't help (apparently it doesn't really re-install the system). In fact, after factory reset my home button stopped working.
Ended up doing a full flash. Pulled up a new system image files from here: SE Xperia Pro - XDA-Developers
And the flashing instructions were here: [25NOV][FLASHTOOL GUIDE] HOW TO for n00bies - G-FACE GUIDE - xda-developers

Notes to add:
No the unlock didn't get lost, but the rooting did. So had to reroot after. Used SuperOneClick.