Unable to install apps from external sources on Android 6.0

[NoelBlakley]

Hello,

I upgraded to Marshmallow and did a full reset in the process so it was a clean install. Now I can't seem to install any apps from outside the Google Play Store. I have enabled the setting of "Unknown sources - allow installation of apps from sources other than the Play Store". When I try install an .apk file I get the following error: "Parse error - There was a problem parsing the package". Specifically I'm trying to install games from the Humble Bundle app, but since this is happening to all games that I try to install I figure the problem isn't with the .apks but with my phone. Any ideas what would cause this?

Any help will be apprecited.

I didn't find the right solution from the Internet.

References:
https://arstechnica.com/civis/viewtopic.php?t=1296791
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Thank you.