Maybe you try to import metadata into a Cumulus Catalog that has not been created inside your network or the asset references in the catalog are not correct or point to servers that are unavailable. Due to a bug in Cumulus that first came up in Cumulus version 2.5 (!) (first AppleScript implementation of scriptability), Cumulus tries to resolve the asset references when metadata is saved in the record by scripting (although this is not necessary). If servers or network zones are missing, Cumulus will try to find them, anyway, and depending on the routing in your network, this might even cause a search on the internet. Of course, this takes 'ages'.

Solution/Workaround: You can switch off the AssetStore modules causing the trouble before importing the metadata. You have to 'Deactivate' the AssetStore modules for Mac OS (Mac OS File System) and Windows (Windows File System) under 'Preferences>Asset Handling Sets' for the Asset Handling Set that is used (usually 'Standard'). The UNIX AssetStore does not cause the problem, so you can leave this active.

Please 'Activate' the AssetStore modules after the metadata import.

The import of categories into the category list and adding these categories to records is a two step task in Cumulus Importer. First, you have to create the categories by importing metadata into the 'Categories' (record) field. After creating the categories, you can assign these categories to the records in a second import task.