
Hi @Tom Molskow ,
You need to deactivate two features to hide the Quick Launch feature for it to take effect.
Here are steps:
1.Site Settings -> Manage site features -> Click Deactivate "SharePoint Sever Publishing" feature.
2.Site Settings -> Site collection features -> Click Deactivate "SharePoint Sever Publishing infrastructure" feature.
3.Site Settings -> Navigation Elements -> Click Off "Enable Quick Launch."
The left navigation bar will be hidden:
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