Hi Welcome to JustAnswer
Before using the Windows 10 Upgrade Assistant, perform these steps:
After completing the above steps, start the Windows 10 Upgrade assistant, and it should complete
Alternatively, I can do the steps for you so I am sending you a remote offer if you wish to use that option instead.
If you can take a minute and use the rating system to rate our session as 3 stars or higher and press Submit so I am credited with helping you.
Windows 10 need quite a good amount of space . Please try to free as much space as you can by taking backup of some of the audio and video files to USB drive and delete all unwanted from recycle bin. It seems like a space issue for me as of now.
Also check if your system in compatible with Windows 10
The 99% issue is not related to the amount of space needed. Please take a look at my reply and remote offer.
After checking above minimum requirement please let me know if you are upgrading from windows 7 to Windows 10 or you have used boot able USB or CD to install windows 10.
I apologize for the confusion of two experts speaking to you at the same time. I will send the other expert a message so it does not confuse you anymore. The amount of space is not the issue so please follow my steps above. Again, I apologize for the confusion.