Default [Q] Please help me fix the error "Couldn't install on USB storage or SD card"

The phone is rooted and unlocked. Other info:

JEWEL PVT SHIP S-OFF RL
HBOOT-2.09.0000
RADIO-1.13.11.0830
OpenDSP-v31.1.0.45.0815
eMMC-boot
Oct 18 2012 15:46:20

Running cm-11-20131208-UNOFFICIAL-jewel, TWRP 2.6.3.0.

This message only happens with one app I try to install 1password, the only program I NEED. It lets me install any other program easily.

I installed 1password once, used for a number of hours, then rebooted the phone and it disappeared; not installed. I tried to download and install it again and keep getting the error "Couldn't install on USB storage or SD card".

I looked around and found a couple solutions:
  • Deleting the asec folder in /mnt/secure/ and deleting .android_secure in /sdcard/.
  • Unmount the SD Card and install.

I deleted the asec folder and .android_secure and nothing happened. Rebooted, nothing happened. I don't have the option to unmount the SD card in Settings > Storage. (See screenshot below)

I also found an older version of 1password's APK and put it in my phone, tried to install and I got an "App not installed" screen. (see screenshot below)

Can anyone help me figure out how to fix this? 1password is one of the few apps I need to run everything else.

Thanks.

EDIT:

I wiped the phone and installed the latest nightly, cm-11-20140105-NIGHTLY-jewel and 1password installed successfully and works!

EDIT 2:

Rebooted the phone, 1password uninstalled itself. I went to the play store to install it again and after the download it said "update successful" and the icon/app showed up again.