To solve this issue, either you have to find the exact installer from a different machine or request Dynatrace to provide it to you. Make sure that the version you are requesting is supported at that moment, otherwise, it will require manual uninstallation from the machine.
If you do not have access to the MSI package yet, please do a manual uninstall of OneAgent from the Windows host. Follow the steps below with admin rights or take help from a local Windows administrator to execute the steps:
Manual uninstall of oneagent in case of msi 1603 error:
Uninstall the agent (if uninstall does not work see the manual cleanup procedure below)
If deleting the service withsc.exefails for whatever reason, you can manually delete the service's registry keyHKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\oneagentmon In case you delete the key manually,be sure to reboot the machine after the last step. Otherwise the service control manager will think the service still exists and re-creating itwillfail if the machine is not rebooted in between.
Remove WinPcap by running C:\Program Files\WinPcap\uninstall.exe(note that the OneAgent uninstaller removes WinPcap but keeps uninstall.exe, this step will remove that as well)
Reboot (optional) - needed for Windows to delete registry keys for paths that were removed.
Hopefully, by following the manual uninstallation steps, you will be able to uninstall the old OneAgent version. However, if the steps provided did not work, please get in touch with product/tech support at Dynatrace.