Dev build 26300 Storage file cleanup

Dear @CrazyKats,

Thank you for posting your question in the Microsoft Q&A forum.

We apologize for any inconvenience you may encounter when using our services/ products. Based on your description, kindly try these workaround steps:

Option 1: Use Disk Cleanup (legacy) to remove Windows.old

Since Disk Cleanup is already detecting the ~30 GB, use it to remove it safely:

• Open Disk Cleanup (cleanmgr)
• Select the system drive (usually C:)
• Click Clean up system files (this is what exposes protected items like Windows.old)
• Check Previous Windows installation(s) (and optionally other safe items like temporary installation files)
• Confirm deletion

Option 2: Use Storage Sense “Run now” (may or may not catch Windows.old on this build)

Even if the Temporary files list is bugged, it’s still worth trying Storage Sense because it can trigger cleanup tasks:

Go to Settings > System > Storage > Storage Sense

Turn it On

Choose your cleanup schedule options

Select Run Storage Sense now

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment". 

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Already stated that Storage Sense is broken. Disk Cleanup works.

Confirm the same issue. Had to use Disk Cleanup to remove Windows.old as System, Storage Sense failed to remove Windows.old.