sechealthui.exe is a program which is most likely NOT a virus. So, if sechealthui.exe is on your system, it is most likely ok, and will NOT be a cause for concern. Even if your PC is clean, it is still recommended to use a good antivirus with a good track record, in order to yourself your PC against viruses and malware.
Normally, this program is stored in C:\Program Files\WindowsApps\Microsoft.SecHealthUI_1000.25992.9000.0_x64__8wekyb3d8bbwe\SecHealthUI.exe.
The MD5 checksum for this file is c0881e1800e3ca77609c5d2e1fb88ecf.
This application is NOT registered as a Windows service. This is very good.
64-bit code has been detected. This program can exploit the full power of a modern PC cpu.
The description present in the file is Windows Defender application.
File version extracted from the file 10.0.25992.1000 (WinBuild.160101.0800).
Producer Microsoft Corporation.
Legal copyright notice © Microsoft Corporation. All rights reserved..
sechealthui.exe appears to have a visible user interface. This means it doesn't run in some kind of stealth mode. Its activity is clearly displayed to the user.
The digital signature is missing from this program. The publisher did not bother to sign it. This is probably bad.
This program does NOT have an uninstall routine stored in registry.