Tool or script for reducing size of Windows\installer folder

Question

My Windows\installer folder is huge (28GB) and I'd like to reduce it. I found reference to the WInstCleaner.ps1, but cannot find a download for it. Is there something better I could use?

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Answer 1

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Hi Gregory,

Thanks for reaching out to Microsoft Q&A Forum. I understand your cautions here, the C:\Windows\Installer folder is special, and cleaning it improperly can break repair, update, or uninstall operations. There is no supported Microsoft tool that safely “shrinks” this folder automatically, and many scripts you’ll find online are risky.

The safest way is uninstalling unused applications

This is the only fully supported way to actually reduce Installer size.

1. Settings > Apps > Installed apps
2. Uninstall software you no longer use
3. Reboot

This removes:

• Program files
• Registry entries
• Cached MSI/MSP files (when safe)

Please note not to these:

• Do not manually delete files from C:\Windows\Installer
• Do not use generic “cleaner” tools
• Do not rely on old scripts (including WInstCleaner)
• Do not follow advice suggesting ownership changes or forced deletes

Symptoms after unsafe cleanup:

• Programs fail to repair or uninstall
• Office update errors
• MSI error 1612 / 1706
• Windows Update failures

Often unrecoverable without reinstalling affected apps or Windows.

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