One of the most common errors we see with an Agent installation on Windows is a 1721 error that looks something like this:
Product: Datadog Agent - Error 1721. There is a problem with this Windows Installer package. The program required for this install to complete could not be run. Contact your support personnel or package vendor.
This is generally due to one of two reasons:
Most frequently, it is due to anti-virus software. In this case, Error 1721 is an Install Shield error code which indicates that the installation process has failed. To correct this:
Another reason is that in some instances, the Windows Installer can become unregistered and needs to be re-registered for installations to function. To correct this:
MSIEXEC /UNREGISTER, and then click OK. Even if you do this correctly, it may look like nothing occurs.
MSIEXEC /REGSERVER, and then click OK. Even if you do this correctly, it may look like nothing occurs, or you may briefly see an hourglass.
Additional helpful documentation, links, and articles: