Thanks for your reply, and apologies for my delay in responding to it. I am running Windows 10 v22H2 Build 19045.6937, and I am enrolled in the Microsoft ESU program for 1 year. I am still running CCleaner v6.39.11548 because I had a terrible experience with CCleaner v7, which I posted about HERE.
The first date that a CCleaner-generated Registry backup file was empty was Jan 15, 2026, which is the same date that the MS Windows Cumulative Update for Windows 10 v22H2 for x64-based System (KB5073724) was installed. Since that date, I have had CCleaner scan my Registry 8 times, including twice today. Every backup file CCleaner has generated is empty except one, which was generated on Jan 23, 2026. Today, CCleaner flagged 95 items in my Registry (the list gets longer with time). I tried having CCleaner backup all of them, and tried checking only 1 item, but the backup files are empty except for the text, “Windows Registry Editor Version 5.0.0". I have also tried saving the backup file to the root of a different drive that is not included in Dropbox or OneDrive.
I don’t know why CCleaner v6.39.11548 stopped exporting the flagged items on Jan 15th, or why the backup file generated on Jan 23rd worked. My update log shows that VS Code and the Nvidia app were both updated in Jan 23, but I do not think those updates are related. Since the KB5073724 was installed on Jan 15th, two MS updates have been installed - KB5075912 - 2026-02 Cumulative Update for Windows 10 Version 22H2 installed on Feb 12, 2026, and KB5077863 - 2026-02 .NET 8.0.24 Security Update, installed on Feb 13, 2026. I may try updating to v7 and hope that it goes better than the first time I updated last October. Since CCleaner v6 is no longer being updated, I need to either switch to v7 or stop using CCleaner.