problems downsizing old video files

[zmdavis]

Hi - I've resumed using Avidemux after a break of many years - I recently retired and am looking to reduce the file sizes of some HD MP4 videos. Some are as big as 15gb, and I want to get them down to about 4gb to make them easy to run on a desktop gizmo I have bought using a Fat32 external  drive.

I want to keep them as fairly standard High Def 1080p files if possible

I'm running version 2.80 on an iMac running Ventura 13.6.6.

Im using standard prefs, and MPEG4 AVC (x264(, AAC (LAV) and MP4v2 Muxer which allow a maximum file size option.

I don't get past first base (fault messages attached) and wonder what I am doing wrong.

I used very early Avidemux versions with no issues whatsoever.

Suggestions most welcome.