Time Machine sparsebundle mounting problems
It's not Time Machine, or anything

It's Spotlight. How?

Spotlight

Spotlight indexes everything. Even on an external disk. My backup .sparsebundle was > 2 TB. My computer can't handle this. Spotlight would index everything before it showed in finder.

Debugging

First, to see what was using the disk. Run:

sudo lsof | grep /Volumes/&lt;Volume Name&gt;


I got something like:

diskimage 519           vihan    4r      mds


and about 4 of those. That meant Spotlight was going haywire.

Disabling

Disabling spotlight is simple. RUN THIS BEFORE TOUCHING THE .SPARSEBUNDLE

sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist


That should disable Spotlight. Now you can double click the .sparsebundle and continue as from this answer