disable TRUST THIS COMPUTER message

Finaly after 2 days I fixed this problem, I will tell and I hope it will work for you, just go to ur control panel and uninstall all the Apple programs + Itune, then restart ur PC and download the new Itune and Trust ur Error for last time and it will work, mine is worked and im so glad im done with that problem,,, good luck.

Had the same "Trust" message pop up on my iPhone 4S. Also wouldn't appear in iTunes. In Windows Device Manager I noticed that the iPhone wasn't appearing in the USB section (should show it as "Apple Mobile Device USB Driver"). That suggests the driver This link walks you through how to find and install the driver:

http://support.apple.com/kb/TS1538

Scroll down to the section that talks about "If the Apple Mobile Device USB Driver is not listed". Took all of 2 minutes. Bingo.

After Apple's 10 or so suggestions, including complicated mscongif and regedit approachs, all failed... I found this, easy enough to follow solution that actually worked. in a single user's post in the forums here somewhere. Can't find it again to say thanks to whoever it was, which prompted me to post it everywhere so everyone else can find it:

(Note: this is for Windows 8, but the solution for other versions is similar - you might need to try a few other folders, but are still looking for "Apple Device" under "Device Manager".)

1. Connect your iPad/iPhone/iPod to your PC
2. Go to: Control Panel > Device Manager
3. Click on: Portable Devices
4. Right click on: Apple iPad/iPhone/iPod > Update Driver Software
5. Choose: Browse my computer for driver software.
6. Go to: C:\Program Files\Common Files\Apple\Mobile Device Support\Drivers

Click okay and everything should suddenly work fine again. (I can't remember if I had to choose "trust" again, but if I did, I only had to do it the once and everything was fixed after that).

Also, if you have an iPad, odds are you going to have to reload its driver as well...

http://support.apple.com/kb/TS1538

Scroll down to the section that talks about "If the Apple Mobile Device USB Driver is not listed". Took all of 2 minutes. Bingo.

I just wish the crappy Bluetooth headset reception that I have on my 4s and 5 was this easy to fix...