I've been fighting the dreaded error 13271 since my Power AIM 120 was new out of the box. It was most aggravating error, as everything would work just fine in the shop. Then as soon as I would go out to do real measurements, these errors would start popping up stopping my scans. I would have to rescan multiple times to get one complete shot. This happened again last night while at a site trying to make a set of quick measurements. Then the thought hit me perhaps the computer is losing focus on the serial port for some other I/O. It turns out this seems to be the case. As soon as I disabled the internal WIFI, everything worked perfectly. I turn the WIFI back on and crash. Just to clarify, the AIM works fine with the WIFI as long as it is connected to a wireless network. When the WIFI is not connected and is searching for a friendly network the AIM scan will crash at irregular intervals. My best guess is that it is something along the lines of I/O system is getting so busy looking for a WIFI signal, it delays checking the serial port too long allowing the AIM to error out.