If you recently upgraded your HP Touchpad to CyanogenMod 9, at first you may not be able to see the tablet as an external USB drive and access its storage space from your computer when connected via the USB cable. Relax, nothing is wrong – the problem is in CyanogenMod 9 configuration, which by default presents the tablet as a camera instead of as an external USB storage.
You can easily fix this with a few changes in settings that are kind of hidden and tricky to access:
2. Scroll down and press “Storage”, then press the three vertically aligned little squares (usual sign for config menu on Android ICS) on top right and press “USB Computer Connection”:
3. Instead of “Camera (PTP)”, select “Media device (MTP)” and you should be good to go.
Another cumbersome thing in this temp version of CyanogenMod for TouchPad is that its USB storage won’t show on your computer as HP TouchPad, but as cm_tenderloin, and after you open it you’ll see a drive named “SD Card”, which indeed is storage space of your HP Touchpad tablet.