I've been using registry cleaner (Registry Mechanic) for years as a solution to my computer's timely slowdown. And cleaning corrupt or unnecessary entries gave some satisfactory results.
But I've found out that cleaning registry entries puts a computer on fifty-fifty - it makes programs to malfunction, very unnoticeable for a period of time though. I noticed that every time I clean and remove entries, the cleaner always detect some sort of unused file extensions, entries on installed programs that deems to be corrupted and some entries marked as unnecessary. Then I always remove whatever the registry cleaner detects even if the program still exist and statically installed.
But the problem appeared clearly a week ago. I opened CorelDraw to edit an image file. When I am going to save such file, the save window doesn't appear anymore and it prompts me to reinstall the program because the registry entries couldn't be found. I've tried to reinstall CorelDraw and the save window appeared it runs smoothly again. After a while, I scanned the registry and noticed that it detected CorelDraw entries as corrupt. Then I deleted it. On the next day, I opened CorelDraw and found out that the problem came back.
The conclusion is, whenever a program is used occasionally, most registry cleaners detects its program entries as obsolete then mark them as unnecessary or corrupt. As a result, programs will not function properly.
The question here is how to detect the real registry entries that are really unnecessary for the system?