Big Sur 11.6.8 update will not install

What won't it install on ? Please read Writing an effective Apple Support Communities Question and then please re-write your question with information that is specific to the device you are attempting to install Big Sur onto.

Got it! Thank you for that information. Please restart the computer in Safe Mode ( Safe Mode ) and attempt to install the Big Sur update while in Safe Mode. After it has re-installed you can re-start normally.

If you continue to have problems, then it may be something installed on your computer. By chance do you have any third party antivirus, cleaning, or any other types of third party "maintenance or security" apps installed?

That is good to hear, if your question was answered please mark it as such, doing this may help another user with a similar problem.