Can't restore iPhone due to low disk space on C Drive for PC

Don't edit, relocate, rename, or extract content from your backup files, because these actions might ruin the files. You can make copies of your backups or delete backups that you no longer need. For more info, see the 'Delete or copy backups on your Mac or PC' section in:

Locate backups of your iPhone, iPad, and iPod touch - Apple Support

See Relocate iOS device backups. Review the rest of the Make a split library portable user tip for advice on organizing the library on secondary storage. Note that the first step of a restore involves archiving the existing set of backup folders, duplicating the amount of space they take up on your computer. This may well prevent a restore from starting, or cause it to fail prematurely. Note also that when a symlink is in place iTunes still checks the free space on the system drive when deciding if there is enough room to commence a restore.

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