Steps to reproduce:
1. Index Manager window
2. Create new Unity project
3. Open Search Index Manager
4. Delete "Assets" index from the list pressin "-"
5. Press ""
6. Select "User"
7. Observe the Console window

Actual results: Error is thrown "FileNotFoundException" in the Console window

Expected results: No errors in the Console window

Reproducible with versions:  6000.0.54f1, 6000.1.14f1, 6000.2.0b12
Can’t test with versions: 6000.3.0a3 (Different Index Manager window)

Tested on (OS): Windows 11

Error:

FileNotFoundException: Could not find file "C:\Users\username\projectname\Library\Search\98957a664bd18c47a3e41b2a0189ef53.33329.b.index"
System.IO.FileStream..ctor (System.String path, System.IO.FileMode mode, System.IO.FileAccess access, System.IO.FileShare share, System.Int32 bufferSize, System.Boolean anonymous, System.IO.FileOptions options) (at <79ca87e32bc54632a9d42d8f2805ee4c>:0)
System.IO.FileStream..ctor (System.String path, System.IO.FileMode mode, System.IO.FileAccess access, System.IO.FileShare share, System.Int32 bufferSize) (at <79ca87e32bc54632a9d42d8f2805ee4c>:0)
(wrapper remoting-invoke-with-check) System.IO.FileStream..ctor(string,System.IO.FileMode,System.IO.FileAccess,System.IO.FileShare,int)
System.IO.File.ReadAllBytes (System.String path) (at <79ca87e32bc54632a9d42d8f2805ee4c>:0)
UnityEditor.Search.SearchDatabase<>c_{_}DisplayClass88_0.<IncrementalLoad>b{_}1 () (at <bc8fcd2950b441a8ad671ae017d26079>:0)
UnityEditor.Search.SearchTask`1+<>c{_}DisplayClass46_0[T].<RunThread>b{_}_0 () (at <bc8fcd2950b441a8ad671ae017d26079>:0)
UnityEditor.EditorApplication:Internal_InvokeTickEvents()

IOException: Sharing violation on path C:\Users\username\projectname\Library\Search\98957a664bd18c47a3e41b2a0189ef53.33332.b.index
System.IO.FileStream..ctor (System.String path, System.IO.FileMode mode, System.IO.FileAccess access, System.IO.FileShare share, System.Int32 bufferSize, System.Boolean anonymous, System.IO.FileOptions options) (at <6460d52f11fa4eaeabfca1cf2e9eca8f>:0)
System.IO.FileStream..ctor (System.String path, System.IO.FileMode mode, System.IO.FileAccess access, System.IO.FileShare share, System.Int32 bufferSize) (at <6460d52f11fa4eaeabfca1cf2e9eca8f>:0)
(wrapper remoting-invoke-with-check) System.IO.FileStream..ctor(string,System.IO.FileMode,System.IO.FileAccess,System.IO.FileShare,int)
System.IO.File.ReadAllBytes (System.String path) (at <6460d52f11fa4eaeabfca1cf2e9eca8f>:0)
UnityEditor.Search.SearchDatabase+<>c__DisplayClass91_0.<IncrementalLoad>b__1 () (at <a077f7aa3c91444ebd3455107f269f2e>:0)
UnityEditor.Search.SearchTask`1+<>c__DisplayClass46_0[T].<RunThread>b__0 () (at <a077f7aa3c91444ebd3455107f269f2e>:0)
UnityEditor.EditorApplication:Internal_InvokeTickEvents()