If you go into the file explorer section will ext SD contents show up?
HTC One M8 powered by SinLess Audiophile v3.5.5 Art/Elite Lunar 3.4.0
---------- Post added at 08:11 PM ---------- Previous post was at 07:59 PM ----------
I got this from a g2 thread. Lots of problems like this with twrp. Never had this crap with cwm.
1.You have to first get the new android sdk.*
2. Then launch a command prompt where the adb sideload program is located. I believe it's \SDK\platform-tools.
3. Place the rom (Zip file) in that same folder as step 2.
4. Boot into TWRP recovery.
5. Select ADB Sideload from Advanced > ADB Sideload.
6. In the command prompt launched from step 2, type in command "adb sideload filename.zip". The "filename.zip" will be changed to the name of your rom, which is located in the same folder as the adb sideload program. You can have a different path, but this makes things easier.
7. The rom should now be transferring to your phone.*
https://www.youtube.com/watch?v=YP1LVOKgwQM
Second half is in English.
I can't verify all this will work so use caution. But it fixed the same problem on the their device.
HTC One M8 powered by SinLess Audiophile v3.5.5 Art/Elite Lunar 3.4.0
---------- Post added at 08:13 PM ---------- Previous post was at 08:11 PM ----------
You may have tried that already since you mentioned adb above.
HTC One M8 powered by SinLess Audiophile v3.5.5 Art/Elite Lunar 3.4.0