*Steps to reproduce:*
# Open a Unity Project
# Open the Index Manager window by going to Window > Search > Index Manager
# Create a new Index by pressing the '+', pressing on Assets and then clicking create. Save the Asset Index with the file name TestIndex
# In the Index Manager window (not the Project browser), rename TestIndex to TestIndexxx. Note how only the name changes but not the file path or the actual file name
# Close the Index Manager window
# Move the TestIndex.index file into a different folder
# Re-open the Index Manager window by going to Window > Search > Index Manager

*Actual results:* The TestIndex index will be missing from the list of indexes

*Expected results:* The TestIndex will still be visible in the list of Indexes and will have correctly kept the reference to the .index file

*Reproducible with versions:* 
* 6000.0.10f1
* 2023.2.20f1
* 2022.3.36f1
* 2021.3.40f1

*Not reproducible with versions:* -

*Can’t test with versions:* -

*Tested on (OS):* Windows 11

*Notes:*
* Sometimes the Index is still visible in the Index Manager after re-opening the Index Manager. However, right-clicking on the Index and clicking 'Force Rebuild' will cause a 'FileNotFoundException' saying it could not find the file.
* Quitting the project and restarting the Unity Editor can cause the Index Manager to re-find the .index files. Performing the reproduction steps will make it lose the file again.