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.```
We've found that 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:
- Disable/Configure any anti-spyware or anti-virus software on your system during the Agent installation process; and
- Check to see if any spyware or adware is installed on your system blocking the completion of install process.
- 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:
- Click Start, click Run, type MSIEXEC /UNREGISTER, and then click OK. Even if you do this correctly, it may look like nothing occurs.
- Click Start, click Run, type 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.
- Try the installation once more
Hopefully if you encounter a 1721 Error, the above steps will get you running in no time!