Mahlerite,
Unfortunately, the issue couldn't be pinpointed. But I think the non-English fonts (in the FontSubstitutes key) and fonts in the per-user fonts folder could be an issue. Wondering if the other Windows 11 computers have the same non-English entries in the FontSubstitutes key. No "DLL missing" or "Access denied" errors weren't found in the logs.
All my PCs have the same multilingual environment.
On the PC not running the Math applications:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\FontSubstitutes]
"Arabic Transparent"="Arial"
"Arabic Transparent Bold"="Arial Bold"
"Arabic Transparent Bold,0"="Arial Bold,178"
"Arabic Transparent,0"="Arial,178"
"Arial Baltic,186"="Arial,186"
"Arial CE,238"="Arial,238"
"Arial CYR,204"="Arial,204"
"Arial Greek,161"="Arial,161"
"Arial TUR,162"="Arial,162"
"Courier New Baltic,186"="Courier New,186"
"Courier New CE,238"="Courier New,238"
"Courier New CYR,204"="Courier New,204"
"Courier New Greek,161"="Courier New,161"
"Courier New TUR,162"="Courier New,162"
"Helv"="MS Sans Serif"
"Helvetica"="Arial"
"MS Shell Dlg 2"="Tahoma"
"Tahoma Armenian"="Tahoma"
"Times"="Times New Roman"
"Times New Roman Baltic,186"="Times New Roman,186"
"Times New Roman CE,238"="Times New Roman,238"
"Times New Roman CYR,204"="Times New Roman,204"
"Times New Roman Greek,161"="Times New Roman,161"
"Times New Roman TUR,162"="Times New Roman,162"
"Tms Rmn"="MS Serif"
"MS Shell Dlg"="Microsoft Sans Serif"
"標準明朝"="MS 明朝"
"@標準明朝"="@MS 明朝"
"標準ゴシック"="MS ゴシック"
"@標準ゴシック"="@MS ゴシック"
"ゴシック"="MS ゴシック"
"ゴシック"="MS ゴシック"
"クーリエ"="Courier"
"タイムズロマン"="Times New Roman"
"ヘルベチカ"="Arial"
On the PC not showing any issue:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\FontSubstitutes]
"Arabic Transparent"="Arial"
"Arabic Transparent Bold"="Arial Bold"
"Arabic Transparent Bold,0"="Arial Bold,178"
"Arabic Transparent,0"="Arial,178"
"Arial Baltic,186"="Arial,186"
"Arial CE,238"="Arial,238"
"Arial CYR,204"="Arial,204"
"Arial Greek,161"="Arial,161"
"Arial TUR,162"="Arial,162"
"Courier New Baltic,186"="Courier New,186"
"Courier New CE,238"="Courier New,238"
"Courier New CYR,204"="Courier New,204"
"Courier New Greek,161"="Courier New,161"
"Courier New TUR,162"="Courier New,162"
"Helv"="MS Sans Serif"
"Helvetica"="Arial"
"MS Shell Dlg 2"="Tahoma"
"Tahoma Armenian"="Tahoma"
"Times"="Times New Roman"
"Times New Roman Baltic,186"="Times New Roman,186"
"Times New Roman CE,238"="Times New Roman,238"
"Times New Roman CYR,204"="Times New Roman,204"
"Times New Roman Greek,161"="Times New Roman,161"
"Times New Roman TUR,162"="Times New Roman,162"
"Tms Rmn"="MS Serif"
"MS Shell Dlg"="MS UI Gothic"
"標準明朝"="MS 明朝"
"@標準明朝"="@MS 明朝"
"標準ゴシック"="MS ゴシック"
"@標準ゴシック"="@MS ゴシック"
"ゴシック"="MS ゴシック"
"ゴシック"="MS ゴシック"
"クーリエ"="Courier"
"タイムズロマン"="Times New Roman"
"ヘルベチカ"="Arial"
The only difference I can see is in the entry
"MS Shell Dlg"
On the PC without issues It is
"MS Shell Dlg"="MS UI Gothic"
whereas in the PC with issues it is
"MS Shell Dlg"="Microsoft Sans Serif"
I doubt this could be the culprit...