Problem is that disk is full of data and Windows regulary warns about no free disk space on it. To solve it you should not delete partition, it is enough to unassign driver letter from it Taken from here.
I just wonder why this 'wanrning' feature is not disabled on this disk?
- Select the Start button, type cmd, select and hold (or right-click) Command Prompt in the list of results, and then choose Run as administrator.
- In the Administrator: Command Prompt window, type diskpart, then press Enter.
- Type list volume, then press Enter. Note the volume number (Volume ###) for the drive letter (Ltr) you want to remove.
- Type the following command, where [volume number] is the volume number you noted in the previous step, then press Enter:
select volume [volume number] - Type the following command, where [drive letter] is the drive letter you want to remove, then press Enter:
remove letter=[drive letter] - The drive letter will no longer appear in File Explorer and Disk Management. You may close the command prompt window.
