For 30 days you still have time to rollback to previous version using the Windows.old folder. If you do not wish to go back to the previous version of Windows then you can delete Windows.old folder and reclaim your hard disk space. Just a note that after you delete Windows.old you will not able to go back to the previous version of Windows.
How To Delete Windows.old Folder
Step 1 : Open Disk Cleanup by typing cleanmgr in Windows Run Command (Windows + R)
Step 2 : Select C Drive and Press OK.
Step 3 : In Disk Clean-up for (C:) click on Clean up system files.
Step 4 : Check Previous Windows Installation and Press OK to proceed.
Step 5 : It will ask are you sure that you want to delete Windows.old, click Yes to proceed.
After following these steps you will no longer see Windows.old folder in your C Drive and it will free up much of the space in C drive. Please Like and Share the Blog, if you find it interesting and helpful.