Omori on PC Game Pass fails to launch.

Just to double check again, only Omori is experiencing this issue even after all these troubleshooting step, right?

I can advise you couple things more to try before contacting the developer for further assistance:

1. If you have both integrated GPU and dedicated GPU

Open windows settings > display > graphics

Once there select "Add a Microsoft app" > Browse and select Omori > Once added click on it > Options > Select Power saving > Try opening the game

(Do the opposite in case you receive the same message, try instead with High performance)

2. I don't want that you format your entire PC and perform a clean windows install, but we can try something similar.

This is create a new NTFS partition

(In case you want to know how to do it: https://www.diskpart.com/articles/partition-ntf... )

After that, create a bootable USB drive with Windows 10 ISO using the creation tool media program:

https://support.microsoft.com/en-us/windows/cre...

(Or if you prefer use Rufus or any third party tool)

Once everything's created, boot your USB, depending on your brand and model the key that opens the boot-device selection menu could be the Esc/F10/F12 keys

Select the option that boots the PC from the USB flash drive once you get in the boot-device selection)

Finally select the recently created partition and install the new Windows system there and once the installation ends every time your PC loads, it's going to ask you which system to run.

If the game runs without any issues there, this means you may need to perform a clean boot/installation for your PC.

Yes I have already done this as part of the process of completely uninstalling Xbox and Microsoft Store Apps and related data.

To clarify: I uninstalled The Xbox App, Microsoft Store App, Xbox Console Companion, Xbox Game Bar, Gaming Services, deleted the contents of the Windows Temp folder and the "AppData\Local\Temp" folder. I also deleted the LocalCache folder and TokenBroker folder inside "Local\Packages\Microsoft.WindowsStore_8wekyb3d8bbwe"

I then restarted my computer and reinstalled The Xbox App, Microsoft Store App, Xbox Console Companion, Xbox Game Bar and Gaming Services. I also made sure Gaming Services was running before launching Omori again. I received the same error as I did before.

I have done as you asked though: uninstalled Gaming Services, reinstalling it and then installed Omori. I still get the same error.

I have uninstalled and reinstalled Omori several times. I did again today and while downloading it had a small error, or that's what the notification bell told me, but the error was resolved before I could do anything.

Right now, I'm only using Windows Security for virus protection. I checked if the firewall was blocking the app but it wasn't so I turned off Real-time protection on Windows Security for a moment and tried to launch the game and the same error occurred.

I'm not sure what to do next.

Just to double check again, only Omori is experiencing this issue even after all these troubleshooting step, right?

Omori is the only game that I am experiencing this type of issue with.
I previously tried launching Young Souls, Undertale, Stardew Valley, and Psychonauts 1 and never got this issue. I have recently launched Forager, Ori and the Blind Forest, Road 96, Yazuka Kiwami 2, DJMAX RESPECT V, Hollow Knight and Psychonauts 2. DJMAX RESPECT V and Road 96 seem to be newly added games so I figured I would test them to see if it's some sort of error with new games, but both of them launched without any issue. Yazuka Kiwami 2 and Psychonauts 2 are the only other games that had loading issues for me, but the issues I experienced with those games were easily discovered and aren't related to Omori's issues as far as I know.

The Biggest problem for me is that I have absolutely no clue what is causing Omori to fail launching. I'm able to launch other games with the same system requirements as Omori, but not Omori itself. I've tried almost every solution I can find on the web and none of it has helped at all. If there was a crash log for the game then I could parse the data and see what's happening, but there doesn't seem to be anything like that for the Xbox App. No other game on the Xbox App has been this difficult to launch.

I only have integrated GPU on this computer.

Creating a new partition seems to be a much more advanced solution than I'm willing to commit to right now. I'm not against trying it but only as a last resort.
A similar solution I hadn't tried until now was to use the Media Creation Tool to install a new Windows 10 OS (the Nov 2021 update) over my old one. I tried that: installed it, kept my old files and deleted my old windows file. I then tried to download Omori on the Xbox App again and it wouldn't download (error: 0x87e00196). I found a solution to that problem, downloaded Omori and after launching it I received the same error as I did before.

After that I ran through the list of solutions I mentioned before, and searched online for any more I could try.
If there isn't any other option available to me then I'll create another partition, but I want to make sure I've tried everything before I do this...

This is everything I've tried so far:
1) Created desktop shortcut for Omori & ran as administrator
2) repaired/reset the game
3) deleted Microsoft Store Local Cache Files
4) deleted Accounts and Cache folders at C:\Users\Username\AppData\Local\Packages\Microsoft.XboxIdentityProvider_8wekyb3d8bbwe\AC\TokenBroker
5) logged into Xbox app and Microsoft Store with same account
6) installed all relevant updates in Microsoft Store
7) updated windows to latest version
8) ran wsreset command
9) repaired & reset Xbox app
10) launched Powershell as administrator and ran several commands*
11) Deleted all Xbox App data in Windows Credentials
12) Ran all services relevant to Xbox App and changed their Startup Type to "Automatic" (IP Helper, Xbox Live Auth Manager, Xbox Live Game Save, Gaming services, Microsoft install service, etc...)
13) uninstalled and reinstalled gaming services
14) uninstalled and reinstalled Omori
15) Ran the SFC & DISM tool
16) installed Omori on a different drive
17) uninstalled earlier Microsoft updates
18) checked if the firewall was blocking the Omori app
19) turned off Real-time protection on Windows Security
20) turned off game mode
21) clicked "Fix it" in Xbox Networking
22) unchecked "Use my sign-in info to automatically finish setting up my device and reopen my apps after an update and restart"
23) checked if Date and Time are set correctly
24) used Media Creation Tool to install a clean OS.

*Commands ran in Windows Powershell:
1) Set-ExecutionPolicy Unrestricted
2) Get-AppXPackage -AllUsers | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest.xml"}
3) Get-AppxPackage *gamingservices* -allusers | remove-appxpackage -allusers
4) start ms-windows-store://pdp/?productid=9MWPM2CQNLHN

If I have to contact the developer for further assistance, what is the best way to do this? Thanks.

I have uninstalled all windows updates from at least 3 months ago except security updates and servicing stacks. I then restarted my computer and downloaded Omori again. Same error as before.

I have tried installing Omori onto another drive before but the only other drives I have are external. It didn't work before but I tried it again. Alas, I received the same error as I did before.

I also tried running SFC tool before, I forgot to mention that. The very first time the tool found some corruptions and fixed them, and since then it hasn't found any other integrity violations. I ran the DISM just now and found no issues there either.

I should mention that my OS is Windows 10 Home Edition. Let me know if you need any other details about my system.

Thanks.