SIA Prerequisite Install Error - Unable to parse [variable('WebDeploy.Version.Compare')]

Question

When setting up a new machine and using Sitecore Install Assistant (SIA) to install the Prerequisites for Sitecore 10.1.1 on Windows 10 64 bit, you may receive the following (abridged) error:

Unable to parse [variable('WebDeploy.Version.Compare')] - 
Exception calling "Evaluate" with "2" argument(s): 
"The running command stopped because the preference variable "ErrorActionPreference" or common parameter is set to Stop

Answer 1

If you're installing Sitecore 10, 10.1, or 10.2, SIA requires Microsoft Web Deploy 3.6 to be installed on the machine as a prerequisite to the SIA prerequisite installation. I assume that this is due to the fact that there's not a publicly available download link for this component. I was able to get around this issue using the following steps:

1. Uninstall any newer versions of MS Web Deploy

2. Manually install Web Deploy 3.6 from here: https://www.microsoft.com/en-us/download/details.aspx?id=43717

3. Remove this item from the Prerequisites.json file:

       "InstallWebDeploy3.6": {
           "Type": "StartProcess",
           "Params": {
               "FilePath": "[variable('WebPlatformCmd')]",
               "ArgumentList": "/Install /AcceptEULA /SuppressReboot /Products:WDeploy36PS",
               "Wait": true
           },
           "Skip": "[variable('WebDeploy.Version.Compare')]"
       },