Memory integrity is one feature of core isolation which regularly verifies the integrity of the code running those core processes in an attempt to prevent any attacks from altering them. We recommend that you leave this setting on, if your system supports it."

Can I turn off core isolation?

Press “Start” and type “Windows Security”. Click the first result under 'best match'. You can find Core isolation details by clicking on “Device Security” in the left sidebar and then clicking “Core isolation details” under the “Core isolation” heading. Under the “Memory integrity” heading, switch the toggle to “Off”.

Is Core Isolation on by default?

It's not enabled by default because it requires some configuration. If you enable this feature, you'll have to allow applications access before they can access files in your personal file folders.