REASON 1: Unique security and permissions set
If files and folders have unique security and permissions set at file or folder level, they are not visible to anyone else.
Check unique permissions at the folder level:
- click the checkbox next to a file or folder
- click on the “i” Document Information Panel
There you can see who has access to the given file or folder.
- click Change permissions, add/remove users
REASON 2: VIEW FILTERING
Files are filtered out via a view. Also, check default views in SharePoint lists and libraries.
REASON 3: REQUIRED METADATA AND CHECK-OUT FEATUR
One of the reasons for missing files is settings some of the metadata.
You can upload but not tag files if you set some of the metadata columns to “required” in the document library or if you drag and drop multiple documents into the library with required columns. The files will be checked out since required metadata fields are not complete.
REASON 4: CONTENT APPROVAL FEATURE
Content Approval feature, which allows to see uploaded and revised files revised to those who uploaded them, is enabled.
REASON 5: SEARCH INDEXING
If indexing is turn off at the library or Site level, the files are not searchable/discoverable via the search box, but it won’t make the files “disappear” from the document library.
Check whether or not indexing is on or off:
Document Library Settings > Advanced Settings > Search
Site Settings > Search and Offline Availability (under Search) > Indexing Site Content
REASON 6: MOVED
The file is moved (or copied and deleted) to a different document library/site altogether.
Execute a global search from the top-level site of the root site collection.
REASON 7: DELETED
Just check the Recycle Bin, you have 90 days to restore files. But you need to be a Site Collection Administrator to see everyone’s Recycle bin.