The best replacement for unallocated space is free space.

The best alternatives to unallocated space are rated as following:
★★★★★  free space
★★  slack space
★  unused

Your alternative for unallocated space is not listed? Suggest!
Speaking about unallocated space, one probably shouldn't forget about primary partition.

Other search terms related to unallocated space and their ratings are:
★★★★★ primary partition
★★★★★ c drive
★★ unallocated space
You have in mind a companion for unallocated space and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of unallocated space in all years. Click on graph for more.
unallocated space
free space
slack space