One of my systems is a Lenovo ThinkCentre M70e 0809 (CPU: Intel Core 2 DUO E7500 @ 2.93GHz, 4GB RAM). I had a bluetooth transmitter/receiver, or dongle, in a USB port of front of the PC for some months. I installed it more or less out of curiosity to see whether I could listen to some music or other content from it using my bluetooth stereo headphone. I just left the transmitter/receiver in the port, thinking this would cause no issues.
Recently, I was reviewing content on the numerous USB flash drives I have accumulated and realized that, when I would connect a flash drive to another USB port on front of this PC, it would initially make an audible sound (the sound normally heard when a flash drive is attached) but would not appear as a drive in File Explorer, and I had no way of invoking to proper procedure for disconnecting a flash drive since the computer simply failed to give it any recognition after that initial audible sound when first connected. At first, I thought I had some defective flash drives. But then, I tired using them on a different PC and they worked fine; they appeared in File Explorer and the proper Eject option was available.
So, I can only conclude that the Lenovo PC will not power both the bluetooth dongle and flash drives at the some time from the two USB ports on front of the PC. I think I'll simply no longer use the bluetooth dongle. I can use my bluetooth headphones with my smartphone and my tablet, so not using the PC dongle is not a big issue. I just thought this info might be helpful to anyone who might encounter this situation.
