I recently encountered the same error and the event viewer displayed an error showing "This implementation is not part of the Windows Platform FIPS validated cryptographic algorithms".

I was able to resolve the error by disabling FIPS mode by doing the following.

Go to Administrative Tools > Local Security Policy > Local Policies > Security Options > System cryptography: Use FIPS compliant algorithms for encryption, hashing, and signing
Switch the flag to disabled.

In my testing I haven’t needed to reboot after changing the setting, but if the issue persists, a restart may be required.

ERROR Dell.Services.SupportAssist.SupportAssistInstaller.InstallSupportAssist - SupportAssist download/installation failed with return code: msihashvalidationfailed

I am getting exactly the same error but even after implementing your proposed solution , the problem is not solved

The following setting is already disabled. Still I am getting the same issue.

"System cryptography: Use FIPS compliant algorithms for encryption, hashing, and signing"

I have noticed another issue with the Support Assist Installer. Check the properties of installer file and you will find the certificate on the installer is already expired on 23/01/2022. I think this is the root cause and not sure why Dell haven't pay attention towards this so far. Issue is unresolved yet.

Hi Dell Support Team,

Can you please assist, even after "System cryptography: Use FIPS compliant algorithms for encryption, hashing, and signing" = DISABLED, I am getting the same error in following location: C:\ProgramData\SupportAssist\Client\Agent\logs\ApplicationLogs

ERROR Dell.Services.SupportAssist.SupportAssistInstaller.InstallSupportAssist - SupportAssist download/installation failed with return code: msihashvalidationfailed

Dear Dell,

Please fix your assist installer, please.

This is crazy, please fix your supportassistinstaller Dell!

Extremely frustrating experience from Dell support, them main hub of their support is not working and no one is bothered. 

HELLO DELL--why do you ignore everyone? This is absurd, your support tool should just install, it is not our job to learn about FIPS or whatever other dependency you have pointlessly built in to this unreliable software, it should just work. First, the existing installation started hanging in the middle every time it was run, so I uninstalled it so I could reinstall and see if that fixed the issue. Perfectly reasonable thing to do. Now I can't reinstall it, so now my expensive Latitude has no software support. Please fix this, keep it simple!

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