First, check out this article how you can use an external drive to facilitate the upgrade:
https://answers.microsoft.com/en-us/insider/wik...
Ways you can free up space:
1 – OneDrive On Demand Files - https://www.groovypost.com/howto/enable-onedriv...
If you have Windows 10 running on a limited capacity device, you probably are looking for the most affordable option to recover some space. Starting with Windows 10 1709, Microsoft reintroduced OneDrive Files on Demand. This nifty functionality lets you keep all your files on OneDrive and only download the ones you need. Our recent article covers all the details how to set it up and configure it.
2 – Disk Cleanup and Storage Sense
Windows 10 is notorious for creating archived files you don’t need. Two features in Windows 10 that can help you with that are Disk Clean up and Storage Sense.
Open Start, type: disk cleanup then hit Enter.
Once Disk Cleanup opens, select the drive where Windows is installed if it’s not already. Windows will scan your hard disk for files it can clean up.
After Disk Cleanup completes its scan, click the button Clean up system files.
This will perform another quick scan including every file that can be removed. Browse through the list then check off what you don’t need. Pretty much everything in Disk Cleanup can be safely removed. If you keep files in Recycle Bin for safe keeping, you probably should remove them.
Storage Sense helps automate storage management by automatically deleting files like temporary files and content in your Recycle Bin. Starting with Windows 10 1709, you can delete files in your Downloads folder that haven’t changed in 30 days. Storage sense can also be set to run automatically when you’re low on disk space.
To set it up, open Start > Settings > System > Storage. Click Change how we free up space.
Enable and modify the settings you would like to be applied when you are running low on space.
Within the Storage interface in Settings, you can get a bird’s eye view of what’s stored on your drive and what might be using up a lot of space. Under Local Drive, click your Local drive where Windows 10 is currently installed.
There you will see a list of locations and the amount of space being used by each. As you can see, Temporary files are using about 7 GBs of space, installed apps and games 6 GBs, and Documents 2 GBs. If you click on one of the locations listed, you are not given many options except viewing the contents of the location and manually removing files you might no longer need.
3 – Delete Data Stored by Apps and Games
Going back to apps and games a bit, sometimes data no longer in use is kept by the app. If you have exhausted all the options previously mentioned, maybe it’s time to see how much data is being stored by each app installed from the Store.
Open Start > Settings > Apps > Apps & features. Select an app then click Advanced options.
Click Reset which will delete all the data stored by the app.
4 – Delete Your Recovery Partition
The recovery partition used to reinstall Windows 10, can eat up a significant amount of disk space. It’s used rarely, if ever, so there is no need to keep it. If that makes you nervous, you can back up your recovery partition to a USB thumb drive, which you can use to reinstall Windows 10 when you need to.
To do that, open Start, type: create the recovery drive and hit Enter.
Connect a USB thumb drive with enough space—16 GB should do—then click Next. At the end of the wizard, you will be asked if you would like to delete the recovery partition. Proceed to do so.
5 – Use Treesize to Find Hidden Large Files (Free)
We previously reviewed Jamsoft’s TreeSize (https://www.groovypost.com/howto/map-hardrive-u...) and found it handy for finding large files not readily visible in Windows 10. The program is simple and easy to set up. Our previous article covers the details for scanning your drive and looking in the right places. Jamsoft provides a portable version of Treesize, so you can run it from a thumb drive and scan your system without using up disk space for the program itself.
6 – Archive Large Files to an External Hard Disk
Storing large files on your local drive that you are not using doesn’t really make much sense these days. Moving infrequently used multimedia, like photos and videos, to an external drive can free up significant amounts of disk space. Because of my Internet limitations, I still need to keep my music locally, so that means my iTunes library probably consumes the most space on my Surface Pro.
Archiving files to an external drive is easy. Before you do that though, you need to invest in an external drive. It’s fairly easy to find one that is really cheap with lots of space. Once you have one, I recommend you check out our guide on how to partition a hard drive for macOS Time Machine and Windows 10 Backups. https://www.groovypost.com/howto/partition-hard...
There are several backup methods you can use, but I always go with the manual method, which involves copying files from your personal folder to a backup folder on your external drive. Select the files or folders then performing a drag and drop action using the right mouse button to your external drive. When the context menu appears, click Move here.
Repeat this step for other folders where you keep large files.
7 – Install an SD Card for Apps.
For devices with an SD card slot, Windows 10 lets you move large apps and games from the main drive. These days, you can get an SD card with as much as 256 GBs of space. This is more than perfect for a system with limited onboard space.
Note: This only works with Microsoft Store apps. Classic desktop apps and those that come built into Windows 10 cannot be moved.
In Windows 10 open Start > Settings > Apps > Apps & features. Select an app or game downloaded from the Windows Store, then click Move.
Click on the Select a drive to move this app to: list box, choose the drive representing your SD card then click Move.
Sources: https://www.groovypost.com/howto/maximize-stora...