I thought I would post this to see if anyone has had this problem and if there was a simple fix.

The removable handle stopped functioning suddenly. The camera does not acknowledge that it is connected so all options in the menu regarding XLR connectors are disabled. I suspect that there is a short in the multi connector at the rear of the handle but I have no way of confirming this. I have since purchased a TASCAM DR-70D as a work around but would certainly like to get the camera back to original functionality.

A first step would be to make sure all the contacts are clean.

I've not read of chronic problems with the handles. Any chance you can get your hands on another camcorder and/or handle and do a swap to determine whether the issue is in the camcorder or handle?

Depending on when and how you bought it might still have warranty coverage (basic period was 1 year if not gray market) and as I recall, some credit cards added to the mfgr's warranty period subject to some limitations.

Just a thought, have you exercised the handle's ON/OFF switch several times just to make sure the switch is really being sensed as ON?

If the handle's switch is OFF (or sensed to be OFF even if it appears to be in the ON position) it will also grey out the menu items and be non-functional.

If that's not the case, then removing the handle and cleaning the contacts as carefully as possible as Don said before reinstalling the handle would be my next recommendation also.

Have you tried a RESET on the camera if cleaning didn't work?

I'm referring to the ON/OFF switch shown in this photo:

A note to an old post. The handle on my 2013 vintage XA20 stopped working this past week. Fiddling with it, it appears that seating the handle fully into the back slot may be preventing connections, possibly due to contact wear.. If I back the handle out a few 1/1000s of an inch and tighten it down it appears to make contact and work.. Will know if a few days if that is the true issue.

Probably getting to be time to retire the unit. The 605 looks tempting, (Too bad the made the LCD panel smaller on the new XA series.)

Has gotten worse! May have to send it in for repair. Too bad the XF605 is still several weeks out.

Repaired by Canon (out of warranty so my cost).

Shipped to the Newport News, VA, repair center
Canon Received it on Nov 8th
Canon Received it on Nov 9th
Canon sent me an estimate on Nov 10th
I authorized repair (credit card payment) on Nov 10th
Canon completed repair Nov 16ht and return shipped.
Received the camcorder morning of Nov 17th.
Overall I am satisfied with the turn around.

Per Canon they do the repair as well as clean check all aspects on unit operation.

Per Canon the problem was the "XLR micon PCB assembly" that needed replacement.
They returned the old board. I believe it sat under the zoom- rocker and stop button on the nhandle and connected vie two ribbon cables.

The board has one IC, a MB9AF131KA, 32-bit micro-controller some surface mounted switches and passive components.