Lightroom Classic doesn't close completely on Windows PC

[Parched]

When I close Lightroom Classic on my Windows PC, it doesn't appear to close completely. If I try to relaunch the program, I get an error message saying there's already a version running, and that I would have to try to open using a different catalog.  I have to reboot my machine to be able to launch Lightroom again.

Any ideas?

[cmgap]

Have you quit using Task Manager? Try that and restart your system to see if that clears up the issue.

[dj_paige]

What version NUMBER of LrC?

What version NUMBER of Windows?

Please tell us the version NUMBERs and not words like "latest" or "up-to-date"

Please also quote the exact unedited word-for-word error message.

[GoldingD]

Please post your System Information as Lightroom Classic (LrC) reports it. In LrC click on Help, then System Info, then Copy. Paste that information into a reply. Please present all information from first line down to and including Plug-in Info. Info after Plug-in info can be cut as that is just so much dead space to us non-Techs.

Sample below as of 7/1/2021

Lightroom Classic version: 10.3 [ 202105281559-8dc50eb4 ]
License: Creative Cloud
Language setting: en
Operating system: Windows 10 - Business Edition
Version: 10.0.19043
Application architecture: x64
System architecture: x64
Logical processor count: 8
Processor speed: 4.0GHz
SqLite Version: 3.34.0
Built-in memory: 16317.1 MB
Real memory available to Lightroom: 16317.1 MB
Real memory used by Lightroom: 1302.8 MB (7.9%)
Virtual memory used by Lightroom: 1586.9 MB
GDI objects count: 746
USER objects count: 2288
Process handles count: 1909
Memory cache size: 252.3MB
Internal Camera Raw version: 13.3 [ 807 ]
Maximum thread count used by Camera Raw: 5
Camera Raw SIMD optimization: SSE2,AVX,AVX2
Camera Raw virtual memory: 299MB / 8158MB (3%)
Camera Raw real memory: 303MB / 16317MB (1%)
System DPI setting: 96 DPI (high DPI mode)
Desktop composition enabled: Yes
Displays: 1) 2560x1440
Input types: Multitouch: No, Integrated touch: No, Integrated pen: Yes, External touch: No, External pen: Yes, Keyboard: No
 
Graphics Processor Info:
DirectX: NVIDIA GeForce GTX 1070 Ti (27.21.14.6089)
 
Application folder: C:\Program Files\Adobe\Adobe Lightroom Classic
Library Path: F:\Files\Pictures\Vacations and Day Trips\Photo Trips\24 Photo Trip September 2019\24 Photo Trip September 2019-v10.lrcat
Settings Folder: C:\Users\goldi\AppData\Roaming\Adobe\Lightroom
 
Installed Plugins:
1) Aurora HDR
2) ColorChecker Camera Calibration
3) DxO PhotoLab 3
4) DxO PhotoLab 3 Importer
5) HDR Efex Pro 2