Hello joaomanoelc,
Thank you for posting here.
1.We can perform a clean boot on Windows 10 and try to open ADAC in clean boot mode to see if it can be opened fine.
2.If we still receive the same error message in clean boot mode, we can uninstall the tool with ADAC, then reinstall RSAT with ADAC in clean boot mode as below:
Open settings->Apps&features->Additional feature->add a feature->click Active Directory Domain Services and Lightweight Directory Services Tools->click Install
3.Open ADAC to see if it is OK.
How to perform a clean boot in Windows
https://support.microsoft.com/en-us/help/929135/how-to-perform-a-clean-boot-in-windows
Best Regards,
Daisy Zhou