Today I'm recovering from a very simple mistake that could have cost me weeks of work if I hadn't made a backup copy in VMware of my application server I am building for XenApp 7.5. I painstakingly installed and tweaked a long list of applications on Server 2008 R2 to be used for the master image in XenApp 7.5 Machine Creation Serices (MCS).
I hit a wall with an issue connecting my XenApp 7.5 DC to vSphere for the MCS connection. I submitted traces to Citrix support, who eventually called it a VMware issue. While waiting for VMware support, I decided to manually create the servers in VMware instead of using MCS so that I could forge ahead in the Citrix upgrade. I can always go back and integrate MCS after the VMware issue is resolved. I sysprepped my application server and created a vm template. After creating my first server from the template, I realized that I FORGOT TO UNCHECK "User cannot change password" for the administrator account before shutting the server down after running sysprep. Great, now I can't login since it forces you to set the administrator password on first login, and the password can't be changed.
What I SHOULD HAVE DONE is to clone my app server, then sysprep the clone and leave the original server intact. Thankfully I had created a backup copy of this server in the lab, so with a few clicks and a short delay I'm making progress again.
Sometimes its the simple things that can cause you the most pain.