Write Protected card lock error, but cards are not locked

I have a Canon 6D

Recently I've been getting an intermittent "CARD Write protect is locked" message. I then can not do anything. It happens with all 6 of my cards, but strangely some seem more sensitive to it triggering the error. Non of the physical switches on the cards are in the locked position or damaged or dirty. They are not cheap cards. All are San Disk Extreme Pro. They all have worked fine in the past. This is a new problem.

I have re-installed the firmware to the camera twice, with the most recent firmware.

has anyone else had this problem?
Any ideas for a fix?

As far as I know the switches on the cards aren't really any switches, but just a piece of plastic which position is detected by the camera. So if this happens, it should be the sensor in the camera that's faulty.

Now I don't have any EOS with SD card, so I'm not sure about this, but it's as I've understood it.

There is a switch in the camera body that detects the position of the card switch. Go to http://camerarepair.bl​ogspot.com …ry-card-locked-error.html then scroll down to the fixes numbered #4, #4A, etc.

I had this happen... The card died shortly thereafter...

Moonshiner wrote in post #16940271
I had this happen... The card died shortly thereafter...

Since he says it happens with all 6 of his cards... do you think all 6 are about to die?

DwainRowe wrote in post #16940302
Since he says it happens with all 6 of his cards... do you think all 6 are about to die?

Doubtful, but stranger things have happened... Especially if they were all exposed to ESD, shock or something else to corrupt them...

John from PA wrote in post #16939885
There is a switch in the camera body that detects the position of the card switch. Go to http://camerarepair.bl​ogspot.com …ry-card-locked-error.html then scroll down to the fixes numbered #4, #4A, etc.

The switch in the camera body is more likely to affect six cards than the likelihood of six cards suddenly failing.