Recover projects lost from the workspace after updating STS/ Eclipse?

Question

I performed an update of SpringSource Tool Suite (workspace name alludes to STS version 3.81) and after the update apparently finished, about 25-30 projects has disappeared from the workspace folder!!! I am using a Macbook Pro (MacOS Sierra). Right now, I just have a .metadata folder in the workspace:

.metadata/
└── version.ini

and contents of version.ini is:

#Wed Apr 18 19:44:34 PDT 2018
org.eclipse.core.runtime=2
org.eclipse.platform=4.6.3.v20170301-0400

1. I used the *nix find command find / -name <names-of-some-files-from-some-of-those-projects> (essentially searching from the root of the hard drive)

2. Spotlight Search

3. Finder Search

Nothing is showing up, so it looks like those folders are gone. How did this happen? I would think the update process would warn me, if it is going to empty the workspace.