Converting a VMware seems to be a trivial thing when using the well-done VMware Converter. But there are some things you need to take into account for several reasons.

This articale could be read as standalone or as follow-up from this article: VMware vSphere Hypervisor (ESXi) with Backup – Step by Step

The following steps describe how to convert from VMware Server 1.x to the VMware ESX Server

Old VMware Server

• shut down the VM. It is better to have an offline machine so we do not have to solve problems which may come with online VMs.
• If you have an automatic startup configured for your VM: disable it to prevent problems which may occour when you start the old and the new VM by accident

VMware Converter

Start the converter. Choose VMware Workstation or other VMware virtual machine. When the machine details can not be obtained try the following

• delete the .LCK files in the working directories where your harddisk files are
• 
• start the VM for some seconeds and shut it down immediatly so the locks on the harddisk files will be released

Choose VMware Infrastructure virtual machine as destination and enter the servername, username and your password.

Keep the old name of the VM or choose a new one

Choose your prefered datastore and choose a hardware version (I recommend the highest  available)

I have experienced problems with DHCP after converting a VMware. I recommend to do the next step, also if you do not use DHCP or other services. You might bypass errors which may occour.

Edit the network adapters in the options.

Select None Network Adapters to be converted. Click the Advanced Settings.

Do NOT power on the converted machine. (Converting can take a long time: up to days… We want to power on the machine when it is ready and when we are here to work with it)

Check the option that you want to install VMware Tools. (recommended)

Click next and recheck your settings and start converting.

vSphere Client

• activate automatic startup – if desired
• Add a new networkcard, Type: flexible
• Start your VM

Converted VM

• login with an admin user and install the VMware Tools

You may also like to install updates while doing restarts.