Running the task 'Migrate SiteTree Linking Task' gives an error if there are no linked pages.
Fatal error: Call to a member function removeDuplicates() on a non-object in G:\localhost\largeherbivore.org\sapphire\tasks\MigrateSiteTreeLinkingTask.php on line 27
Update Line 27 to:
// Databases like MSSQL will give duplicate results - remove them
// This would normally be fixed by using SELECT DISTINCT, but DataObject::get() doesn't support it
if ($linkedPages) $linkedPages->removeDuplicates();
avoids the error.