Photoshop Will not update

Use Adobe CC Cleaner Tool to wipe old PS off your system.  And retry with a clean install.

https://helpx.adobe.com/creative-cloud/kb/cc-cleaner-tool-installation-problems.html

But before you upgrade, check the new system requirements to be sure your machine can support it. 

- https://helpx.adobe.com/photoshop/system-requirements.html
- https://helpx.adobe.com/photoshop/kb/photoshop-cc-gpu-card-faq.html

See here:
https://helpx.adobe.com/creative-cloud/kb/creative-cloud-desktop-app-installation-stuck.html
https://helpx.adobe.com/creative-cloud/kb/stop-responding-downloading-apps.html
https://helpx.adobe.com/creative-cloud/kb/troubleshoot-install-logs-cc.html
https://community.adobe.com/t5/get-started/updating-adobe-creative-cloud-stuck-at-39/m-p/10916241?page=1
https://helpx.adobe.com/creative-cloud/kb/creative-cloud-app-doesnt-open.html
I had a similar issue.

Make sure that you have all Windows updates that are available.

The one thing that was causing it for me, believe it or not, was that I needed to do a clean installation of the latest Studio graphics driver from the NVIDIA website. After doing that and restarting, all was OK.

Moving thread to the Download & Install forum from Photoshop ecosystem