TeamViewer insider builds are unpublished pre-release versions of the TeamViewer full version on Windows.
TeamViewer contains a setting called Receive insider builds, which you can find at the top of the Advanced page in the TeamViewer options.
If you activate this setting, the TeamViewer client will automatically update to the latest pre-release versions ofTeamViewer.
This gives you the opportunity to test new features before they are released to the wider public, and give us feedback about them.
If you activate this setting, your TeamViewer client will search for new updates on a daily basis.
To revert to the public version of the TeamViewer software from an insider build, you have to uninstall TeamViewer.
Then you can install the regular TeamViewer version available on the website. Make sure that the setting Receive insider builds remains disabled.