To: babyMx3
Hello,
Sorry but we have not received any support requests from you.
We still recommend you to use new version 5.2 of AVS Video Editor. There should not be problems with preview after files are
cached.
Please reinstall the whole AVS software suite using the instructions
here and install the latest versions of AVS programs.
If it does not solve the issue, please attach your mp4 file properties (right click on the file in Media Library>Properties).
Best regards.