VirtualBox NS_ERROR_FAILURE (0x80004005) [FIXED]

It's a common problem of VirtualBox and I looked through tons of pages and didn't find a fix, maybe because there isn't? Good think I found a fix!!

 That's the error message: 

Could not open the medium '/drive/username/partition/virtual_machine_name.vdi'.
VD: error VERR_FILE_NOT_FOUND opening image file '/
drive/username/Data/virtual_machine_name.vdi.vdi' (VERR_FILE_NOT_FOUND).

NS_ERROR_FAILURE (0x80004005)

More details on the error:

Result Code:
NS_ERROR_FAILURE (0x80004005)
IMedium {4afe423b-43e0-e9d0-82e8-ceb307940dda}

It happened with me because I have the virtual machine on a different partition, and I started it without mounting it, that ruined the installation.

How to fix it?

I had to uninstall VirtualBox and install from scratch..
That's the only fix, uninstall VirtualBox.
When you reinstall it, it should work fine, No need to delete the virtual machine.
Did you have this problem before? How did you fix it?
I know this didn't “fix” the problem, and maybe you aren't running Ubuntu and it happened with you.
I'll post more if I found anything.
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