title: VM does not boot - "Content ID mismatch" in machine log. How can I fix this?
body: <p>What I discovered recently is that it can be dangerous to <strong>mount a virtual disk (a <code>*.VMDK</code> file)</strong> in VMWare <strong>from outside of the VM.</strong> </p>
  
  <p><strong>Description of the scenario:</strong>
  I've created a new Virtual Machine (let's call it <strong>VM B</strong>) where I booted from an ISO image containing an <em>imaging tool</em> (such as <em>Parted Magic</em>) which readed from such a virtual disk (belonging to a different Virtual Machine, named <strong>VM A</strong>) in order to write the content to a different external physical disk. That virtual disk file was only mounted and I did not write any changes to its structure.</p>
  
  <p><img src="https://i.stack.imgur.com/Yumcb.jpg" alt="enter image description here"></p>
  
  <p><strong>Issue:</strong>
  After I have shut down the <strong>VM B</strong> and tried to boot up the other <strong>VM A</strong>, to my surprise it did not boot any more. Looking into the machine's logfile (vmware.log), I found a <em>"Content ID mismatch"</em> error in <strong>VM A</strong>'s log.</p>
  
  <p>What happened? How can I fix this?</p>