nathabonfim59

For those of you running Windows 10/11 and bought the program using the Microsoft Store.
Here is a solution. Again, not advised, but it worked for me.
 
1. Enable the option to open explorer in a separate process
2. Install the "Get ownership" context menu
3. Open your CMD as an administrator
4. Go to the WindowsApps folder of your application
 
>> Hang on, we are halfway there! 😁
 
5. Now the "Take Ownership" of the Designer/Photo/Publisher.exe.config
6. Open the file with notepad or other program and make the changes suggested by @lacerto 
7. Save the file and you are done! 👏 👏
 
Common errors
 
Hope this helps someone, and you don't need to waste 4 hours searching and combining solutions from random places on the internet. 😅

I do not think that we really know whose "fault" the recent crashes and anomalies with e.g. fonts, linked resource and profile lists (the latter in Affinity Photo only) are, but we know that after installation of a recent update to .NET 3.5 and 4.8 (and 4.8.1) these errors do happen with Affinity apps (and most probably with other, too, that have enabled data virtualization in context of list controls), both on Windows 10 and 11.
There is a known, easy workaround to disable the functionality that causes these issues in apps that use WPF based user interface and controls. Those users of Affinity apps that choose to keep the recent .NET 3.5 and 4.8.1 by default automatically applied recommended system updates (instead of rolling them back to avoid these rather limited Affinity-affected issues), might want to apply the easy fix given in this post to keep the updates and also avoid the issues caused by them.
If you decide to try this, please understand that you do it “on your own risk” so the instructions presented here are given just as user-to-user tip in a situation where Serif support has chosen to recommend unrolling of a recommended Windows update (that also contains security fixes), instead of giving detailed information of the problem. IMO, users who choose to unroll a security related system update also do it “on their own risk”, but most of them probably inadvertently, unless they have read the KB article related to the update they are advised to uninstall. Personally I’d definitely keep all the system (security) updates (and keep on receiving further Windows updates, rather than taking a risk of blocking miscellaneous new updates because of having unrolled one possibly being a pre-requisite for further recommended and automatic fixes).
I have no competence of making statements on whether these updates, which in addition to security fixes also contain several improvements that make the affected controls more stable, also have changes that are themselves directly causing new issues (that is, if they contain clear bugs), or whether the fixes are such that they break apps that have used certain features that in the improved versions require handling and processing, but omission of which did not cause problems in earlier versions. So far Microsoft has not provided any further fixes to the affected .NET modules, and the KB articles related to these updates state that MS is not aware of any issues related to applying these recommended updates. As far as I know this is the latest KB article related to Windows 11:
https://support.microsoft.com/en-us/topic/october-11-2022-kb5017271-cumulative-update-for-net-framework-3-5-and-4-8-1-for-windows-11-version-22h2-535ac8db-c89b-43f7-abd7-a3c3240320e6
It is quite possible that such issues exist and that there will be an official fix some time in the future, but as long as such information is not made public to users (either by MS or Serif), I think that for most users it is best to allow recommended system updates and just try to live with the app issues for the moment (until getting more detailed information), as they seem to be such that can easily be either avoided or worked around (the issue with linked resources is more serious, however, and if not attended, can make it practically impossible to work with the project).
Anyway, those who don’t mind fiddling with the app setting text files and making a couple of tiny changes in them to avoid the .NET 4.8 update related issues in Affinity apps, can choose to do the following:
NOTE: You should make these changes only if you have .NET 4.8 (or a sub version like 4.8.1) installed due to recent Windows update. Please check the update history to see that this is so. Disabling the data virtualization setting has no effect unless you actually have the update active, but then you should not experience the mentioned issues in the first place)
1)      The files to be edited in case you have Serif-store purchased versions are:
C:\Program Files\Affinity\Publisher\ Publisher.exe.config
C:\Program Files\Affinity\Designer\ Designer.exe.config
C:\Program Files\Affinity\Photo\ Photo.exe.config
In case you have Microsoft Store purchased apps, I am not sure if it is wise or even possible to tamper with the configuration files, even if their location can easily be revealed by using Task Manager and opening the location of running Affinity executables.
2)      The changes to be made in each of these text files are the following:
a) In line that states the sub version of the .NET runtime version, enter 4.8 instead of 4.7.2 or something else that states the current version:
    <startup>
      <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.8"/>
    </startup>
b) In line that states whether data virtualization should be used in context of list controls, change the current value from “true” to “false”, as follows (alternatively you could delete all three lines, that is, the <appSetting> block, but it is enough to just set the value of the only setting in this block false):
  <appSettings>
    <add key="IsVirtualizingStackPanel_45Compatible" value="false"/>
  </appSettings>
3)      Save the changes (you need to run your text editor in Administrator mode), then launch your Affinity apps to see if this has fixed the problems with font lists (any Affinity app) and color profile conversion (Affinity Photo).
I cannot tell whether changing the runtime version number can have any negative effects, but if so, then it is easy enough to cancel the changes and revert the original settings. For that purpose it is a good idea to make backups of the original setup configurations before making changes to them.
I hope this user-based help is considered acceptable on the forum. I am giving it basically because I find it disturbing that Serif support currently appears to advise users to uninstall security involved recommended updates also related to issues the cause of which is not necessarily the mentioned system update, basically just to see if it “could be”, making users of release products kinds of testers (instead of spending some time and examining the cases themselves) -- and without giving any further details of the nature of the updates that they ask users to uninstall (exact KB numbers are not given, either, and e.g. there are already four or five 3.5. and 4.8 updates for Windows 11, and additionally feature updates that might either include them or be blocked because of being dependent on them).
Instead, it is basically implied that the update in question is a Microsoft blunder that the users should get rid of in order to make their system operable again [UPDATE: or, that because the issue has arisen spontaneously after a system update, it is a responsibility of MS to fix the problem as if Serif were not in power of doing anything to the matter themselves]. No notice is given whether the alleged “bug” is actually acknowledged by MS so that a fixed update could be expected in due time, or whether users of Affinity apps should permanently avoid Windows updates involving .NET components, whether security related or not.
I have not seen any publicly given information on whether a kind of feature-disablement fix (or “workaround”) shown above might at some time point be provided officially by Serif, as well, in an event it seems that there will be no Microsoft provided update that one way or another manages to implement the made improvements and security fixes without causing breaking of existing apps. And whether it is provided for all 1.x versions since they all seem to be affected.
In case this information is considered inappropriate to exist on the user forum and is estimated to possibly cause more harm than good, I apologize for posting it, and hope the moderators will remove it. The intention was nevertheless good, and due warnings were given.
UPDATE: The latest Microsoft cumulative update as of October 25 to .NET 3.5, 4.8 and 4.8.1 still does not seem to fix the issue (tested on Windows 10 and 11), and in the release article MS still claims their view of not being aware of any issues related to the update:
https://support.microsoft.com/en-us/topic/october-25-2022-kb5018341-cumulative-update-preview-for-net-framework-3-5-and-4-8-1-for-windows-11-version-22h2-6bb1451c-7782-4a1f-bfdf-31140d49ee99
It means that this problem has now lasted already over a month (and the modules causing this problem in Affinity apps have been re-distributed already in a number of different cumulative updates, some containing security related fixes, as well). I do not know if rolling back the update could cause delay in update of any feature, quality and security updates but e.g. on my Windows 11 computer there is one feature update and eleven Windows 11 related quality and security updates that have been auto-installed after September 17, when the modules causing this issue were first time installed on this computer. The next official monthly cumulative update will happen on Tuesday Nov 8, and if this will not fix the issue, I would be a bit worried about the status of the problem (as there is a chance that there will be no auto-fix to the problem from MS). 
UPDATE2: For me, the patch Tuesday update as of Nov 8 2022, also including (once again) an updated .NET 3.5 and 4.8.1 module (in addition to making several other system updates), unfortunately did not bring a fix to the issues experienced in Affinity apps because of changes affecting WPF data virtualization, so the above mentioned fix is still necessary, if you choose to keep Microsoft updates.
The release note of the latest .NET 3.5 and 4.8.1 update for Windows 11, 22H2, also including a security fix: 
https://support.microsoft.com/en-us/topic/november-8-2022-kb5020622-cumulative-update-for-net-framework-3-5-and-4-8-1-for-windows-11-version-22h2-b28f2daf-af6d-4182-a960-05c607a27ef5
UPDATE: There is now official 1.10.6 update for Windows that properly fixes this issue. Please use that instead of the workaround. The updated version will overwrite any manual changes made to the app setting file so you do not need to restore anything to get the apps behave as planned.
 

Alternatively, you can disable Nahimic in the specific application the problem is occurring. 
1. Open the file below as administrator in notepad. I
If yours is not a Dell device, no worries, just google "Nahimic blacklist - <your brand here>" and you'll be able to locate the file.
2. Add the executable name for the applications you use at the begging of the file (one per line):
Just restart the service (or the machine) and you are done. Worked like a charm.