Hi Angela,
Thanks for contacting Syncfusion Support,
We have checked the reported query “Installing Syncfusion build deletes existing gauge tools ” from our end. Follow the steps suggested in the below KB article link and send us the zip file which consists of Syncfusion Installer logs generated by our tool. Also please share the installed old build version and the new Build version details and if possible share the issue reproducing video for the same . It would be much helpful for us to analyze the reported issue
Regards,
Bharathi R