VirtualBox Issue: "Create Virtual Machine" wizard only shows 32 bit guest versions in "Version" dropdown

Recently I have came across very strange problem while creating Virtual Machine(VM) using Oracle VM VirtualBox.I was planning to install the 64 bit CentOS as the Guest OS on my 64 bit Windows Host but the Version drop-down in the Create Virtual Machine wizard didn't have any 64 bit options. Through VirtualBox documentation, I have checked the details of supported Host OS & Guest OS and found that it also supports 64 bit Guest OS. Therefore it's a problem with my system configuration. 

In this "How To" guide, we would discuss how to resolve the above issue so that if you face the similar issue then you could also easily troubleshoot the issue.

VM creation using VirtualBox Issue: "FATAL: No bootable medium found! System halted."

Have you came across below error while trying to start your newly created Virtual Machine (VM) using Oracle VM VirtualBox :

The error states that : FATAL: No bootable medium found! System halted.

This error message tells us two things:

• No bootable medium found: we haven't specified the Guest OS for our Virtual Machine (VM) while configuring the VM system configurations. 
• System halted: in absence of an OS, how can any system start, that's why our VM system is halted.

This article is kind of How To Guide to show the steps with screenshots to fix the above issue.

Error response from daemon: Docker push already in progress

It's relatively common that one would tend to interrupt the current ongoing process of uploading assets on the cloud and try it again when it's taking too much time to upload. With Docker, you might face below issue i.e "Docker push already in progress" if you interrupt the docker push command and try running it again for publishing your image to the Docker repository i.e Docker Hub.


The error states that: Error response from daemon: push <username>/<repository> is already in progress.
From the error message, it's clear that push/upload is still running in the background but we are unable to see it's progress. If one can wait to finish the current docker push then the problem will automatically resolve. 

In this article, we would discuss the circumstances that may leads to the above issue and the resolution of this issue i.e how to get back the docker push progress bar.