Question OTA to 4.4.2 failed ["/system/bin/app_process" has unexpected contents.]

Can anyone help me.

Having problems with the OTA update from 4.4 to 4.4.2

I'm running Stock OS rooted with TWRP, BusyBox 1.2.1.1 & SuperSU 1.80

When I run the update TWRP gives the following error in the log:

Code:
I:Switching packages (TWRP)
I:Set page: 'install'
I:Set page: 'flash_confirm'
I:Set page: 'flash_zip'
I:Set page: 'flash_zip'
Installing '/cache/4f6d2fc7377dbb48caecaa658bb139da2b063b33.signed-occam-KOT49H-from-KRT16S.4f6d2fc7.zip'...
Checking for MD5 file...
I:Cannot find file /cache/4f6d2fc7377dbb48caecaa658bb139da2b063b33.signed-occam-KOT49H-from-KRT16S.4f6d2fc7.zip.md5
Skipping MD5 check: no MD5 file found.
I:Zip does not contain SELinux file_contexts file in its root.
Verifying current system...
file "/system/bin/app_process" doesn't have any of expected sha1 sums; checking cache
failed to stat "/cache/saved.file": No such file or directory
failed to load cache file
script aborted: "/system/bin/app_process" has unexpected contents.
"/system/bin/app_process" has unexpected contents.
E:Error executing updater binary in zip '/cache/4f6d2fc7377dbb48caecaa658bb139da2b063b33.signed-occam-KOT49H-from-KRT16S.4f6d2fc7.zip'
Error flashing zip '/cache/4f6d2fc7377dbb48caecaa658bb139da2b063b33.signed-occam-KOT49H-from-KRT16S.4f6d2fc7.zip'
Updating partition details...
I:Data backup size is 2457MB, size: 13231MB, used: 8064MB, free: 5299MB, in data/media: 5606MB.
I:Unable to mount '/usb-otg'
I:Actual block device: '', current file system: 'vfat'
I:Set page: 'flash_done'
I:Set page: 'clear_vars'
I:Set page: 'main2'
I:Set page: 'advanced'
I:Set page: 'confirm_action'
I:Set page: 'action_page'
I:Copying file /tmp/recovery.log to /data/media/0/recovery.log
Think it's something to do with BusyBox and how it installs, is it fixable without a total wipe?
Had the same issue with the OTA upgrade to 4.4 (had to do a total wipe and lost a lot of files on the virtual SDcard as a result).