It sounds like your security software is seeing the update of GSAK as a new program and not allowing GSAK to perform certain functions. This can happen with some security software even if you've previously added GSAK.exe to the "white list" of trusted programs in your security software.
Open your security software and try adding GSAK.exe to the trusted programs list. If that works, you may have to do this each time you update GSAK (this is an issue with your security software, not GSAK). If adding GSAK.exe to your security program's trusted programs list does not fix things, please restart your computer in Safe Mode (with networking) and test running the exports in Safe Mode (with networking). If it works in Safe Mode (with networking) we know some other software is getting in the way and can continue to troubleshoot down that road. If not, we can look at other possible causes.
PS The current version is 8.7.1.55 - if you have 8.7.0 you'll need to update (Tools>Check for Newer Version of GSAK) once you get things working.
Open your security software and try adding GSAK.exe to the trusted programs list. If that works, you may have to do this each time you update GSAK (this is an issue with your security software, not GSAK). If adding GSAK.exe to your security program's trusted programs list does not fix things, please restart your computer in Safe Mode (with networking) and test running the exports in Safe Mode (with networking). If it works in Safe Mode (with networking) we know some other software is getting in the way and can continue to troubleshoot down that road. If not, we can look at other possible causes.
PS The current version is 8.7.1.55 - if you have 8.7.0 you'll need to update (Tools>Check for Newer Version of GSAK) once you get things working.