To restore alarms on vCenter Server or move custom alarms from a source vCenter Server:

1. Download the file 1032660_copyalarms.zip (attached to this article) and extract the files to your vCenter Server. This .zip file contains the script copyalarms.ps1. Caution: The script in this article is provided as a best effort, and is not supported by VMware. If you choose to use the script, you do so understanding the risk associated with its use, and that VMware takes no responsibility with the associated risks.Note: To run the script, you need two instances of vCenter Server. One vCenter Server must have the default alarms present. You can install a new vCenter Server on a virtual machine that can be discarded afterwards, or use another production environment vCenter Server that has the alarms present. The other vCenter Server is the destination server that does not have default alarms present.
2. Right-click copyalarms.ps1 and choose Edit.
3. Specify the source and destination vCenter servers to execute this script. For example:
   
4. Change the if statement to read ‘if ( $true )’ to copy all alarms from your vCenter Server. For example:
   
5. Click the green arrow to execute the script copyalarms.ps1. For example:
6. When the script has executed, verify that the alarms have successfully migrated to the destination vCenter Server.

Source: http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1032660