Hi there,
Just to let you know you aren't alone; same symptoms.
In my case, I have isolated it down to something specific to a particular AppleID/account. By this, i mean I can load my iCloud/appleID details into the iCloud for Windows app when I click the iCloud Passwords button which launches "icloudpasswords.exe", authenticates via Windows Hello and it works fine.
However, if i used a separate AppleID account (a family members which is the only one that exhibits this issue), whilst it logs into iCloud for Windows fine, 2FA authenticates etc., iCloud Drive and photos looks like theyre working, the actual passwords app will crash if youy try to open it. It authenticates, via Windows Hello, and then it crashes.
Windows reports that icloudpasswords.exe has stopped responding with a C000005 error in the faulting module objc.dll (which is a file inside C:\Program Files\WindowsApps\unique-path-to-icloud-for-windows-app-folder)
I can replicate this issue on a fresh installation of Windows 10 or Windows 11. I mean completely fresh up-to-date windows update, minimal video card drivers and that's it. No security software except the default Microsoft Defender.
I can replicate this issue on two separate Windows machines, in addition to the above.
Further to this, the same behaviour is observed here : I can't open iCloud Passwords on my Windo… - Apple Community - where the user reports the Chrome password extension works. This is exactly the same scenario for me, in addition to the above. I can tick the Chrome Extension in iCloud for Windows settings, and since it doesn't seem to open icloudpasswords.exe, I can actually use chrome and have it autofill passwords etc despite the fact that opening the icloudpasswords.exe directly (as in, via the shortcut inside the main iCloud for Windows app, > "Open iCloud Passwords")
A piece of relevant background: the troublesome (family member's) AppleID account did actually work in the past without issue. When i set it up a few months ago, I used iCloud for Windows with the Passwords option ticked so i could log in and move most of their accounts over (manually) so they didn't have to type them in manually via phone. This worked, and i moved about 20 accounts or so.
Then the family member has continued to use their AppleID / iPhone, and stored more and more data in their keychain which possibly might have created a particular record/entry that seems to trip up icloudpasswords.exe when it opens.
I'm not sure if iCloud for Windows has received an update since the above transpired in early May 2023.