Is it possible to create a different format for sub-folder within the same document library?
For example, have one sub-folder with tiles and then the following sub-folders they click into from that page would be a list format
Unfortunately, this is not possible using SharePoint out of the box capabilities.
The views in library are created at document library level and not at folder/subfolder level.
So, if you change any library view settings (like list/tile format or filtering/sorting, etc.), the change will be applied at all levels (library, folders and subfolders).
Hence, you cannot have different view format for folders and subfolders.
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