We have purchased and deployed a number of Latitude E7440's and E7240's and we are running into an issue with some of the E7240's. When waking from sleep while on battery power, the machine will start to wake, the display will come back and I can move the cursor but within a second or two, the cursor will freeze and the machine will become totally unresponsive. This almost always doesn't happen on AC but it has once or twice. I've set the power plan to 1 minute and tested over and over again and it is reproducible every time. The only way to recover from it is to power off the machine via the power button and restart it.
Right now this is happening on the original end-user's machine and 1 other deployed E7240 we were able to get back and test. I have a couple of other E7240's deployed and I have an email out to the end users to bring them in so we can check them too.
I've upgraded the BIOS from A09 to A13. I've tried switching wireless control from Intel to Windows. I've updated to the latest drivers on the Dell support site.
Machines are i7, 256GB SSD with 8GB RAM running Windows 7(64) Enterprise