Generate SQL fails when comparing to SVN

I'm unable to generate a migration script when comparing SVN to a new database. I'm copying our existing production database's schema using SSMS-> Generate scripts to create the new database, which I then compare to the committed changes in SVN. Comparing against existing databases seems to work fine.

After I click "Deploy" and select the option to generate the script, the "Generate SQL" spinner times out and I get this message:




However I can right click each item individually and the sql will generate fine.

From what I can tell in the log files, this part may be relevant:

06:05:27.202|Debug |SOCRepoMRUListerServ|1 |scriptsXml: <?xml version="1.0" encoding="utf-16" standalone="yes"?>
<!--
SQL Compare
SQL Compare
Version:12.3.3.4490-->
<ISOCCompareLocation version="1" type="SvnLocation">
<RepositoryUrl>https://svn.myserver.com:8080/svn/path/</RepositoryUrl&gt;
</ISOCCompareLocation>
06:05:27.202|Debug |SOCRepoMRUListerServ|1 |migXml:
06:05:27.203|Error |SOCRepoMRUListerServ|1 |Error while reading SOC xml from registry
System.NotSupportedException: Specified method is not supported.
at RedGate.SqlSourceControl.Client.MigrationsV1.NotSupportedMigrationsV1Client.GetMigrationsV1FolderLocation(String xml)
at RedGate.SqlServer.Comparison.Shared.UI.Services.SOC.SOCLinkService.ParseMigrationsV1LocationXmlFragment(String migrationsXml)
at RedGate.SqlServer.Comparison.Shared.UI.Services.MRU.SOCRepoMRUListerService.ToSocRepo(String scriptsXml, String migXml)
06:05:27.204|Debug |SOCRepoMRUListerServ|1 |scriptsXml: <?xml version="1.0" encoding="utf-16" standalone="yes"?>

thanks,
Eric