What parts of the Windows 7 system subfolders can safely be deleted?

I am running out of space on my C: drive on my Windows 7 machine and using JDiskReport to analyse where the storage is being used I find these big ones:

C:\Windows\assembly 3.7GB
C:\Windows\Installer: 9.6GB
C:\Windows\System32: 10.4GB
C:\Windows\winsxs: 24.5GB (of which "Other" is 21.8GB)

C:\Users\All Users\Package Cache: 5.4GB (most in "Other")

Are any of those targets for either deletion or some form of cleanup?

Is there a utility that could get rid of anything *really* not necessary (and that won't break my system)?
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

David Johnson, CD, MVPOwnerCommented:
run up the disk cleanup manager and select cleanup system files

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
KhaiPiAuthor Commented:
I tried that and it only reported 186MB of files that it could clean-up which would hardly even make a dent.
Use the Cleanup utility to free up space (right click "Computer", select "Manage", then "Disk Management", right click the partition you have the OS on, select "Properties", and in the "General" tab click on "DiskCleanup".

Besides that you can also make just a small pagefile on C: (about 256MB is enough, and a system managed one on D:.

Delete the contents of C:\Windows\SoftwareDistribution\Downloads.

disable hibernation (open an elevated cmd prompt and enter powercfg -h off).
IT Pros Agree: AI and Machine Learning Key

We’d all like to think our company’s data is well protected, but when you ask IT professionals they admit the data probably is not as safe as it could be.

David Johnson, CD, MVPOwnerCommented:
you've already moved your documents/music/pictures/videos to another drive?
KhaiPiAuthor Commented:
Yes David, I have all of those on my D: drive.
KhaiPi, I am pretty sure you did not follow David's advice to the T. When in disk cleanup, did you click on the button "clean up system files"? Then, you would have had more options and the GBs will fall.
The system files cleanup option was added with a patch, see whether you have it installed: https://support.microsoft.com/en-us/kb/2852386
KhaiPiAuthor Commented:
I was initially confused by which disk cleanup tool to use but the three selected solutions combined enabled me to reclaim quite a bit of disk space.

Thanks very much!
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Windows 7

From novice to tech pro — start learning today.