How to free up space after Bitlocker encryption

[jp_d_cruz]

I have three drives in my laptop. I turned bitlocker on to the third, 1TB, drive. My drive had more or less 500GB free space when i started. After the encryption (which really took a while), the free space was only around 30GB. So i turned off Bitlocker (also took a while) but the size remained around 30GB. I set hidden and system files to be visible but i don't see any new files or folders created. All the visible folders size only sum up to around 500GB. I turned bitlocker on again but this time with the used space option only, but still the free space remained at around 30GB.
Any idea how to recover free space without reformatting?

Laptop runs Windows 10.

 

[rgd1101]

use windirstat https://windirstat.net/ to see where the space go

 

[jp_d_cruz]

use windirstat https://windirstat.net/ to see where the space go

Thanks. Problem solved!