Hangs During Backing Up Catalog

I created a collection set and then another collection inside of it. I really wanted the second collection set to be the parent of the first, so I moved it up one level. Lr did not update the collections and appeared unresponsive. I decided to close Lr and backup optimize the catalog and it never completed. It got hung in the Backup Catalog Step. I tried to close Lr and it will not close. The hard disk light kept flashing. I had to reboot the PC. Here's my system information.

Windows 10 Home

Version 10.0.17134 Build 17134

System Type x64-based PC

Processor Intel(R) Core(TM) i7-2600K CPU @ 3.40GHz, 3401 Mhz, 4 Core(s), 8 Logical Processor(s)

BIOS Version/Date American Megatrends Inc. 2501, 7/21/2014

SMBIOS Version 2.7

Embedded Controller Version 255.255

BIOS Mode Legacy

BaseBoard Manufacturer ASUSTeK COMPUTER INC.

System Directory C:\WINDOWS\system32

Boot Device \Device\HarddiskVolume5

Locale United States

Hardware Abstraction Layer Version = "10.0.17134.1"

Installed Physical Memory (RAM) 32.0 GB

Total Physical Memory 31.9 GB

Available Physical Memory 10.9 GB

Total Virtual Memory 63.9 GB

Available Virtual Memory 37.2 GB

Page File Space 32.0 GB

Lr was consuming 67% of the memory and it kept increasing.