Download Blocked by Microsoft Defender SmartScreen?

29 Jan 2026

After downloading OGCS, if it’s been released recently, you may be faced with the alert below when attempting to run the installer or the portable application executable.

🔐 It can be resolved safely! See below for guidance

It just takes time for each new release to build reputation with Microsoft before the warning is removed.

Unblocking the installer download:-

1. For OGCS_Setup.exe you may be able to simply click More info and then Run Anyway
   🔐 You can confirm the file is authentic and safe as it will show the publishers name
   

2. If not, right-click the OGCS_Setup.exe file and select Properties

3. In the bottom right hand corner, click the Unblock checkbox and then OK.
   🔐 Again, you can confirm the file is authentic and safe as it will have been “signed” by the developer
   

4. Execute OGCS_Setup.exe

Unblocking the portable zip:-

1. After extracting the zip file contents, right-click the OutlookGoogleCalendarSync.exe file, select Properties and then check Unblock as per the above image

2. If there is still a problem, try unblocking all the extracted files. The fastest way to achieve this is:-

   1. Winkey+R and type powershell
   2. Change directory to the extracted files
      cd C:\my\extracted\files\directory
   3. Get-ChildItem | Unblock-File
   4. Now run OGCS by double clicking the executable.

Happy Syncing!