Here is a work around (below) for this issue. I tried the above method must the Info.plist file want not in the format shown) -
1. Log into your Mac as an account with administrator rights
2. Open TextEdit - Go > Applications > TextEdit
3. Type a letter into the blank document
4. File > Save As... > save the docuemnt as "BSD" (without quotes), leave the default file format with is "Rich Text Format" and save it somewhere you can easly get to e.g. your desktop
NOTE: You have now created a "BSD.rtf" file. You will need to change the file extension to .pkg and move this file to the location the symantec installer is searching for, which is /Library/Receipts
5. Next, locate the file you created, select the file, then press the cmd + i keys (cmd key is also know as the apple key) this will give you the information about the file
6. Expand the Name & Extension section (if not already extended) and change the file name from "BSD.rtf" to "BSD.pkg" (both are without quotes). Press Enter (or Return) and you will be asked to confirm which file extension you would like select " - Use .pkg".
7. Go > Computer > navigate to /Library/Receipts
8. Copy the "BSD.pkg" file here.
9. Run the Symantec Endpoint Protection 12.1 installer (you will need to logoff at the end of the installation)
10. After logging back on go to - Go > Computer > navigate to /Library/Receipts and delete the file you created - "BSD.pkg"