Mojave 10.14.06 / Quicktime does not play mp4 / unknown error -101

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Level 1

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Mojave 10.14.06 / Quicktime does not play mp4 / unknown error -101

Hi all,

Mojave was running well and everything was great when suddenly Quicktime stopped playing mp4. Safari also stops playing in Internet classes (which also contains mp4).

Does someone knows what should be done?

Thanks and best regards,

Leopoldo Knett

Posted on Aug 29, 2019 12:27 PM

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Answer 1

Top-ranking reply

Urquhart1244

Community+ 2024

Level 10

142,794 points

Aug 29, 2019 9:30 PM in response to LKnett

I would suggest to use these methods to see where the real issue is:

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Answer 2

Sep 5, 2019 2:44 AM in response to LKnett

If the issue is with the QuickTime software, then you could re-install the system software. Doing so should keep your personal files and preferences as they are, unless you opt for an erase/‘clean install’.
If you may have installed questionable software that may interfere with normal operations, then you can check with Malwarebytes and/or get a report for EtreCheck.
If the issue is in hardware, then I think the issue should also manifest with other file formats and other applications. Checking RAM modules is best done by removing/replacing the modules one-by-one and then testing for the issue.