Is your Images disappeared from your Phone or Desktop after sync.
If its disappeared from the desktop, please check that you are working on right catalog.
Also check if you can your images on the Cloud.
Cloud Link: Adobe Photoshop Lightroom
Sign In and Check the collections.
Let us know if it helps.
Hi Tessie, did you connect a new Lr Desktop catalog with your Adobe-Id. Normally Lr Desktop comes up with a caution alert that your account is already connected to a different catalog with the question if you want to sync the new catalog. When you confirm with yes this would delete all the back-end data. Lr Desktop only supports a single catalog connection to your Adobe-id. - Guido