I recently upgraded to a RAZR M and can not connect to my PC with the USB cable. I have tried cable that came with phone and others and get the same message that USB driver did not install correctly. The phone did an update of the operating system less than a week after getting it so I am not sure what is up.
Also tried the MTP and PTP settings to see if that made any difference without help. I know my last phone had a setting for mass storage USB and I do not see that on the Droid.
Anyone else have this problem and been able to fix it?
I had some trouble with the drivers that install from the phone.
Best go to the Motorola support site and download and install the windows driver.
Not an answer for you, yet I had this issue on my new Razr HD. The SD card was sort of accessible, I could transfer one file and then the directory info and transfer would get all goofy... However, on the HD there is an option for mass storage. It just needs to be set. Refer to the manual. Out of the box mine was set for MTP. Once it is set to mass storage it is not accessible by the phone (to find the stuff you transferred as mass storage) until you go back to the same menu and set it back to MTP.
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It has been working for me, I use the data cable that is part of the charger, plug I into a USB port, pull down the status screen, tap on "Connected as a media device", then check "Camera (PTP)", then i can access my phone files via Windows explorer. You will see "XT907" as a new drive. This is after my JB update.