Ok @tqFan you have me both totally confused and intrigued. 
I am failing to understand why my app cannot process the files in your “My Games” directory.
I am losing sleep and sanity over this and it is niggling me endlessly. There must be some reasonable solution here.
As @powbam mentioned, there are numerous funnies in the community as well with users having issues with options and other stuff not saving properly. Your issue may be related and relevant and maybe we can get an idea of what is causing this.
Can I pick your brain and use your scenario to figure some of this stuff out as a “Guinea Pig” (don’t tell @Maya she might have us arrested for animal cruelty 
) ?
I have developed a GDViewerDebug app that logs step by step what the GDViewer is trying to do both to the screen and in a log file.
The initial form looks like this if it passes the file access permissions to it’s OWN install directory.
When you run the test it will give a detailed log of what it is finding in the Grim Dawn save directory and will report on any errors or even warnings (will touch on that later with your setup).
Example of a run looks like this is successful.
Notice that in this case I have intentionally added 3 rubbish entries to the save directory and the GDViewer will ignore them exactly as the debugger log will state.
Log files are generated which will be a great help to me if anyone is experiencing weird errors.
One interesting observation in YOUR @tqFan save dir debug output is that you actually have 3 character directories with a DOUBLE underscore as a directory name? Either you created those characters yourself with a name that starts with an underscore, or something else renamed them to that. They are not BAD characters and they do process as a valid GD char in the viewer - not sure what Grim Dawn does with them or why they have double underscore prefixes.
(-Anyone modder have an answer?)
Look at the output of the debugger for your setup …
2020/05/13 15:14:31 - Looking for character directories in “C:\Temp\GD_Chars\save_TQFan\main”
_Eaint Clestwood OK
_Khione OK
_Korvan Wyrm OK
_Raiden OK
_Sakura OK
_Sirocco OK
_Xorton OK
_Zeo OK
__Arundel OK
__Li Ming OK
__Sirocco OK
11 Valid Grim Dawn character directories found
0 Entries ignored
Checking header read of the character player.gdc files
_Eaint Clestwood : Eaint Clestwood - Oppressor
_Khione : Khione - Trickster
_Korvan Wyrm : Korvan Wyrm - Vindicator
_Raiden : Raiden - Warder
_Sakura : Sakura - Witchblade
_Sirocco : Sirocco - Conjurer
_Xorton : Xorton - Warder
_Zeo : Zeo - Paladin
__Arundel : Arundel - Druid : WARNING Name does not match standard directory naming
__Li Ming : Li Ming - Spellbreaker : WARNING Name does not match standard directory naming
__Sirocco : Sirocco - Occulist : WARNING Name does not match standard directory naming
8/11 Characters have been validated as genuine Grim Dawn characters
GDViewer.exe may have issues - please resolve above errors or investigate warnings
For a comparison I added some nonsense files to my test environment and the debug goes like this …
2020/05/13 15:16:01 - Looking for character directories in “C:\Temp\GD_Chars\save_Dev\main”
CrapFile.txt : IGNORED : not a valid Grim Dawn character directory!
player.gdc : IGNORED : not a valid Grim Dawn character directory!
_Andromeda OK
_Beast Master OK
_Broken : IGNORED : the player.gdc file is missing!
_Bryll OK
_Caster Blaster OK
_Cyklone OK
_Darkosis OK
_Dong Zhou OK
_Evilyn la Grave OK
_Father Bull Mahone OK
_Flintlock OK
_Green Manalishi OK
_Havok OK
_Jacobus Krieg OK
_Jane Doe OK
_Kane OK
_Katrina OK
_La Muerte OK
_Laagatha OK
_Leofrik of the Light OK
_Lilitha OK
_Piledriva OK
_Ricochet OK
_Roland OK
_Santa el Diablo OK
_Satanica Pandemonia OK
_Sherrif Jesse Bourbon OK
_Shokk OK
_Skorch OK
_Stormblaze OK
_Torkamada OK
_Tyfoon OK
_Victor Zero OK
_Xexbeth OK
_Xibeth OK
_Yellow Peril OK
_Zong Chang OK
36 Valid Grim Dawn character directories found
3 Entries ignored
Checking header read of the character player.gdc files
_Andromeda : Andromeda - Trickster
_Beast Master : Beast Master - Cabalist
_Bryll : Bryll - Elementalist
_Caster Blaster : Caster Blaster - Paladin
_Cyklone : Cyklone - Druid
_Darkosis : Darkosis - Cabalist
_Dong Zhou : Dong Zhou - Warlord
_Evilyn la Grave : Evilyn la Grave - Arcanist
_Father Bull Mahone : Father Bull Mahone - Apostate
_Flintlock : Flintlock - Tactician
_Green Manalishi : Green Manalishi - Dervish
_Havok : Havok - Blademaster
_Jacobus Krieg : Jacobus Krieg - Witch Hunter
_Jane Doe : Jane Doe - CLASSLESS
_Kane : Kane - Witchblade
_Katrina : Katrina - Spellbreaker
_La Muerte : La Muerte - Reaper
_Laagatha : Laagatha - Sentinel
_Leofrik of the Light : Leofrik of the Light - Battlemage
_Lilitha : Lilitha - Apostate
_Piledriva : Piledriva - Warder
_Ricochet : Ricochet - Sorcerer
_Roland : Roland - Death Knight
_Santa el Diablo : Santa el Diablo - Oppressor
_Satanica Pandemonia : Satanica Pandemonia - Warlock
_Sherrif Jesse Bourbon : Sherrif Jesse Bourbon - Deceiver
_Shokk : Shokk - Elementalist
_Skorch : Skorch - Commando
_Stormblaze : Stormblaze - Saboteur
_Torkamada : Torkamada - Purifier
_Tyfoon : Tyfoon - Archon
_Victor Zero : Victor Zero - Vindicator
_Xexbeth : Xexbeth - Conjurer
_Xibeth : Xibeth - Mage Hunter
_Yellow Peril : Yellow Peril - Ritualist
_Zong Chang : Zong Chang - Shieldbreaker
36/36 Characters have been validated as genuine Grim Dawn characters
GDViewer.exe should execute OK with no issues
Here is a link to the debugger.
Anyone is welcome to use this tool as well to see what apps actually detect in their Grim Dawn save directory.
See later posts for updated.
but you were wrong… they aren’t AoM characters - they are the Vanilla-only toons.
