Unable to reopen untitled file with notebook

[rebornix]

Issue Type: Bug

In today's Insiders I can't reopen untitled file with notebook anymore

Unable to open 'Untitled-1': The file working copy resource untitled:Untitled-1 does not have an associated file system provider..

VS Code version: Code - Insiders 1.56.0-insider (Universal) (0123d26, 2021-04-29T06:21:54.461Z)
OS version: Darwin x64 20.3.0

System Info

Item	Value
CPUs	Intel(R) Core(TM) i9-9980HK CPU @ 2.40GHz (16 x 2400)
GPU Status	2d_canvas: enabled gpu_compositing: enabled metal: disabled_off multiple_raster_threads: enabled_on oop_rasterization: enabled opengl: enabled_on rasterization: enabled skia_renderer: disabled_off_ok video_decode: enabled webgl: enabled webgl2: enabled
Load (avg)	8, 8, 7
Memory (System)	32.00GB (0.33GB free)
Process Argv	--enable-proposed-api ms-vscode.vscode-notebook-history --enable-proposed-api vscode.notebook-editing --enable-proposed-api vscode.vscode-test-resolver --enable-proposed-api donjayamanne.kusto --crash-reporter-id 1a907bbd-fa02-4595-81e0-63e1648afb31
Screen Reader	no
VM	0%

[lramos15]

Do you know if the notebook uses the untitledDocumentData API? I think this is working copy stuff but I'm not 100% sure.

[bpasero]

/duplicate #121974