For some weird reason, after updating Virtualbox to the latest version 6.1.2, I was unable to install the corresponding extension pack. It would just hang while installing and there was no way to close it other than using End Process in Task Manager. So I thought, F that and proceeded to run my saved VM, except it wouldn't run due to USB 2.0 enabled in it and that required the extension pack. Now I was in a serious pickle (I hate losing my work especially when a saved VM session is lost). On a lark, I changed the extension of the extension pack to zip. Double-clicked it and it opened in Winrar! There was another file of the same name in it, just without any extension. I extracted that and gave it the zip extension and whaddayaknow? It opened again revealing a set of files. I opened Virtualbox's installation folder and went into the extension pack folder (C:\Program Files\Oracle\VirtualBox\ExtensionPacks). Checked the XML file in the Oracle_VM_VirtualBox_Extension_Pack folder and turned out that it was the currently installed extension pack for the previous version. Made a copy of this folder, deleted everything in the original folder and placed the files from the newer extension pack version into this folder. Double clicked my saved VM with a beating heart and SUCCESS! Everything is back to normal. Hope this helps anyone else having such trouble.
Which brings me to my question: How many other files have you all experienced to be actually zip files in disguise? I know xlsx and docx are zip files because I was curious why the same file's size was smaller in the x format so changed the extension to zip and turned out it had xml files in it. Relate your similar experiences, if any.