As the title says i can't seem to enable it, it's greyed out, tried everything i could for the day but nothing works. Things ive tried :
-disable display over other apps -disabling google play -developer mode( The developer tools , can't use the 'press 5 times on build' method because it has pin locked) -factory reset -tried downloading an apk using adb, got the app in but it needed an update and wasn't able to because unknown apps wasn't enabled.
Your help is greatly appreciated
This will be confusing to read: do you have an application that can install applications installed?
Unlike Android phones, you can only enable "install from unknown sources" if you have a file manager or other application capable of installing an app.
Edit: actually, I've recently reset my device and I see the same thing, even after I've installed a file manager. I had to enable developer mode as well. Once I did both of those things I was able to enable installing unknown apps, but on a per-app basis. As in, you select which apps are allowed to install apps. I've not tried to install via adb on here, not sure how that will work.
I thought I had to push it 7 times, not 5.
Make sure your in the admin account
It would be very helpful if we knew what make and model of device you are using.