On Creating the "Complete" Asset Index under "Quick Search" from the "Preferences" window, the editor throws FileNotFoundException, refer attached video.

Steps to repro:
1. Create a new project
2. Window > Package Manager > Quick Search > Install (Preview.5 - 1.6.0)
3. Edit > Preferences > Quick Search
4. Asset indexing mode > Complete > Create Index

Actual Result:
FileNotFoundException thrown on creating Complete Asset index

Expected Result:
Complete Asset Index created gracefully

Occurring on:
2020.2.0a5, 2020.1.0b5 with package version 1.6.0 - preview.5

Working fine on:
2020.2.0a5, 2020.1.0b5 with package version 1.6.0-preview.4, 1.5.2

Environment:
Windows 10 and macOS 10.14