thank you for the thorough analysis and report. The important part of the report is this one.
sudo /Applications/Avast.app/Contents/Backend/hub/modules/014_fileshield.sh fix; echo $?
Password:
+ BASE_DIR=/Applications/Avast.app/Contents/Backend
+ PLIST=/Applications/Avast.app/Contents/Backend/launch/com.avast.fileshield.plist
+ SERVICE_ID=com.avast.fileshield
+ FILESHIELD_BIN=/Applications/Avast.app/Contents/Backend/services/com.avast.fileshield
+ RUN_DIR='/Library/Application Support/Avast/run'
+ PID_FILE='/Library/Application Support/Avast/run/fileshield.pid'
+ KEXT_ID=com.avast.FileShield
+ KEXT=/Applications/Avast.app/Contents/Backend/drivers/AvastFileShield.kext
+ case "$1" in
+ /sbin/kextload /Applications/Avast.app/Contents/Backend/drivers/AvastFileShield.kext
/Applications/Avast.app/Contents/Backend/drivers/AvastFileShield.kext failed to load - (libkern/kext) system policy prevents loading; check the system/kernel logs for errors or try kextutil(8).
27
The value 27 means, that the drivers were not allowed or at least macOS thinks they were not allowed. In your screen shot, you were missing the Allow button. Did you have the Preferences open while installing Avast? Apple Preferences are not really smart, so they do not refresh the UI when you install any SW while Preferences are open. You need to close and re-open them for the Allow button to appear.
Another thing you could try is to run the suggested kextutil command. It has a more verbose output on what is going on.
Please let us know any updates. Hopefully we will be able to get this to work, otherwise a bug report to Apple will be needed. They already had similar issues in macOS 10.13 that were fixed in 10.14, but they keep changing it internally and might have broken something again.
Yes, as my original information stated, the allow was missing, and the image was there as proof.
Ran the kextutil - and it gave the following:
Kext loading serialization lock busy; sleeping (89 retries left).
Kext rejected due to system policy: <OSKext 0x7fb1b4f52910 [0x7fff8dd38d10]> { URL = "file:///Library/StagedExtensions/Applications/Avast.app/Contents/Backend/drivers/AvastFileShield.kext/", ID = "com.avast.FileShield" }
Diagnostics for /Applications/Avast.app/Contents/Backend/drivers/AvastFileShield.kext:
I then uninstalled Avast.
I’ve ensured the system preferences were closed (pretty certain I did that before).
Then ran the installer again… used standard install, allowed for all users…
Gave the ok for the installer to install new applications…
Closed the installer.
Chose continue with free (for now)…
Clicked through the messages…
When the app screen was revealed, it was in passive mode.
Clicked on core shields.
Allowed Avast to open the system preferences
Unlocked the preferences
But still no Allow.
Clicked leave core shields off (for now).
Re-ran the kextutil.
sudo kextutil /Applications/Avast.app/Contents/Backend/drivers/AvastFileShield.kext
Password:
Kext rejected due to system policy: <OSKext 0x7fb90ca62bf0 [0x7fff8dd38d10]> { URL = "file:///Library/StagedExtensions/Applications/Avast.app/Contents/Backend/drivers/AvastFileShield.kext/", ID = "com.avast.FileShield" }
Diagnostics for /Applications/Avast.app/Contents/Backend/drivers/AvastFileShield.kext: