Hi Speedy-V:
The registry cleaner is working as expected with my CCleaner Free Portable v6.39.11548.
As a test I ran my v6.39.11548 registry cleaner today to clean up one entry that was pointing to a Malwarebytes v5.4.6 installer I originally saved on my desktop, and after saving the cc_20260125_091821.reg file in the location I selected (i.e., in a folder I had previously created at C:\Users\<myusername>\Documents\PC Troubleshooting\CCleaner\Registry Backups) …
… the cc_20260125_091821.reg file contained:
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Classes\Local Settings\Software\Microsoft\Windows\Shell\MuiCache]“C:\Users\ljmac\Desktop\mb5-setup-consumer-5.4.6.227-147.0.5453-1.0.106235.exe.FriendlyAppName”=“mb5-setup-consumer-5.4.6.227-147.0.5453-1.0.106235.exe”
After rolling back to CCleaner v6.39.11548 did you ensure Settings | Advanced | Show Prompt to Backup Registry Issues is ENABLED, and if so are you sure you’re looking in the correct folder you selected to save .reg files created by CCleaner v6.39.11548?
Dell Inspiron 15 5584 * 64-bit Win 10 Pro v22H2 build 19045.6809 * Firefox v147.0.1 * Microsoft Defender v4.18.25110.6-1.1.25110.1 * Malwarebytes Standard v5.4.6.227-147.0.5453 * Macrium Reflect Free v8.0.7783 * CCleaner Free Portable v6.39.11548 * HDCleaner Portable 64-Bit v2.095