Keywords keep reverting to XMP (embedded) but I only want to keep XMP (sidecar)

[musashi77]

Ive been working through categorizing all my older photos for months, when I imported they all had some old flat keywords that Ive been removing and replacing with a new set of hierachial keyword, however Ive been running into this issue on quite a few photos, after organizing all the keywords exactly how I want once I "write back" the files it always wipes my new keywords and brings back the original keywords that I want to remove completely from the database.

Using the Metadata Analyst App, Ive been able to identify that no matter what I do, write back always strips the 'sidecar' and replaces everything back to the 'embedded' as you can see below. I need to remove the XMP (embedded) keywords but I dont know how? Ive looked at the 'Metadata Mechanic' App but Im at a loss as to how to use it or where to start with it. Is it possible to get a few pointers on how exactly to target removing just the  XMP (embedded) keywords?

Keywords
XMP (embedded) keywords found.
'Rides'; 'Theme Parks'
XMP (sidecar) keywords found.
'_00_Sorting|_repeating_metadata_01'
XMP (embedded) hierarchical keywords found.
'Rides'; 'Theme Parks'
XMP (sidecar) hierarchical keywords found.
'_00_Sorting|_repeating_metadata_01'
Different XMP keywords in embedded XMP record and sidecar file.

[Mario]

Which file format are you using?
Embedded XMP metadata is mandatory for JPG, PSD, PNG, TIFF, DNG, PDF, MP4 to be compatible with the XMP standard.
Sidecar files are used for RAW files and other formats only.

Mixing embedded XMP and XMP in sidecar files is not recommended and will cause issues. Like in this case.
You cannot have two sources of truth for the same metadata value.

IMatch automatically embeds XMP metadata in the file formats required by the XMP standard.
It will detect and merge XMP metadata found in sidecar files, too. This is because, by definition, XMP sidecar files belong to all files with the same name in the same folder.

By the MDA report, you have different keywords in the embedded XMP record and the sidecar file. Problem.
Why do you also have a sidecar file? Are there multiple files with the same name in the same folder, some using XMP in sidecars and some using embedded XMP?

Your small excerpt from the MDA does not even tell us which file format you use, what your folder structure is etc.

[musashi77]

This sample came from an MP4, these are really old pictures, so I really don't know where or why they have sidecars, most likely due to one of the many applications used in the past. I have tried removing the sidecars while troubleshooting and it doesn't change anything, even without the sidecar I cannot clear the embedded keywords. All sidecars are sitting together with the original file as they should be, happy to remove them if they are not required.
You say It will detect and merge XMP metadata found in sidecar files, too. however there isnt any merging happening, its just reverting back to whatever was originally there.

It looks like all the old video clip files have sidecars (avi, mp4, mov) and the rest appear to be RAW (.orf)

Metadata Analyst Results. Version 2020.14.2. 7/23/2022 12:22:52 AM
File analyzed: \\qnap6\PICS\PHOTOS_ALL\2010 - 2013 Toronga 401\2012\1201.January\1201 (2) Japan\120111 - Mie\VID\2012-01-11_Mie_VID (1001).MP4
Errors: 0
Warnings: 1

Warning: [XMP] Embedded XMP record (XMP Core 5.5.0) and XMP sidecar file (photools.com IMatch 20.14.0.2 (Windows)) found.

[Mario]

Warning: [XMP] Embedded XMP record (XMP Core 5.5.0) and XMP sidecar file (photools.com IMatch 20.14.0.2 (Windows)) found.

This means that there is a sidecar file.

In version 2021.8.2, IMatch changed how it manages XMP for MP4 files. It now always embeds the XMP metadata, no longer using XMP sidecar files for MP4.
This is how XMP storage has evolved, and how most of the major applications out there now manage XMP for MP4.

Did you read the release notes and performed the steps required to import XMP metadata from sidecar files into MP4 files?
The release notes contained a link to this dedicated help page, which explains the steps: https://www.photools.com/help/imatch/#xmp_import.htm

Do that first, then remove the XMP sidecar files (unless you have other files in the same folder which depend on the XMP file).