diff --git a/plugins/3MFReader/ThreeMFWorkspaceReader.py b/plugins/3MFReader/ThreeMFWorkspaceReader.py
index 9046c5e6f3..c18e823658 100644
--- a/plugins/3MFReader/ThreeMFWorkspaceReader.py
+++ b/plugins/3MFReader/ThreeMFWorkspaceReader.py
@@ -3,9 +3,13 @@ from UM.Application import Application
 
 from UM.Logger import Logger
 from UM.Settings.ContainerStack import ContainerStack
+from UM.Settings.DefinitionContainer import DefinitionContainer
+from UM.Settings.InstanceContainer import InstanceContainer
+from UM.Settings.ContainerRegistry import ContainerRegistry
 
 import zipfile
 
+
 ##    Base implementation for reading 3MF workspace files.
 class ThreeMFWorkspaceReader(WorkspaceReader):
     def __init__(self):
@@ -30,30 +34,88 @@ class ThreeMFWorkspaceReader(WorkspaceReader):
         if nodes is None:
             nodes = []
 
-
+        container_registry = ContainerRegistry.getInstance()
         archive = zipfile.ZipFile(file_name, "r")
 
         cura_file_names = [name for name in archive.namelist() if name.startswith("Cura/")]
 
+        # TODO: For the moment we use pretty naive existence checking. If the ID is the same, we assume in quite a few
+        # TODO: cases that the container loaded is the same (most notable in materials & definitions).
+        # TODO: It might be possible that we need to add smarter checking in the future.
+
+        # Get all the definition files & check if they exist. If not, add them.
+        definition_container_suffix = ContainerRegistry.getMimeTypeForContainer(DefinitionContainer).suffixes[0]
+        definition_container_files = [name for name in cura_file_names if name.endswith(definition_container_suffix)]
+        for definition_container_file in definition_container_files:
+            container_id = definition_container_file.replace("Cura/", "")
+            container_id = container_id.replace(".%s" % definition_container_suffix, "")
+            definitions = container_registry.findDefinitionContainers(id=container_id)
+            if not definitions:
+                definition_container = DefinitionContainer(container_id)
+                definition_container.deserialize(archive.open(definition_container_file).read().decode("utf-8"))
+                container_registry.addContainer(definition_container)
+
+        # Get all the material files and check if they exist. If not, add them.
+        xml_material_profile = None
+        for type_name, container_type in container_registry.getContainerTypes():
+            if type_name == "XmlMaterialProfile":
+                xml_material_profile = container_type
+                break
+
+        if xml_material_profile:
+            material_container_suffix = ContainerRegistry.getMimeTypeForContainer(xml_material_profile).suffixes[0]
+            material_container_files = [name for name in cura_file_names if name.endswith(material_container_suffix)]
+            for material_container_file in material_container_files:
+                container_id = material_container_file.replace("Cura/", "")
+                container_id = container_id.replace(".%s" % material_container_suffix, "")
+                materials = container_registry.findInstanceContainers(id=container_id)
+                if not materials:
+                    material_container = xml_material_profile(container_id)
+                    material_container.deserialize(archive.open(material_container_file).read().decode("utf-8"))
+                    container_registry.addContainer(material_container)
+
+        # Get quality_changes and user profiles saved in the workspace
+        instance_container_suffix = ContainerRegistry.getMimeTypeForContainer(InstanceContainer).suffixes[0]
+        instance_container_files = [name for name in cura_file_names if name.endswith(instance_container_suffix)]
+        user_instance_containers = []
+        quality_changes_instance_containers = []
+        for instance_container_file in instance_container_files:
+            container_id = instance_container_file.replace("Cura/", "")
+            container_id = instance_container_file.replace(".%s" % instance_container_suffix, "")
+            instance_container = InstanceContainer(container_id)
+
+            # Deserialize InstanceContainer by converting read data from bytes to string
+            instance_container.deserialize(archive.open(instance_container_file).read().decode("utf-8"))
+            container_type = instance_container.getMetaDataEntry("type")
+            if container_type == "user":
+                user_instance_containers.append(instance_container)
+            elif container_type == "quality_changes":
+                quality_changes_instance_containers.append(instance_container)
+            else:
+                continue
+
         # Get the stack(s) saved in the workspace.
-        container_stack_files = [name for name in cura_file_names if name.endswith(".stack.cfg")]
+        '''container_stack_suffix = ContainerRegistry.getMimeTypeForContainer(ContainerStack).suffixes[0]
+        container_stack_files = [name for name in cura_file_names if name.endswith(container_stack_suffix)]
         global_stack = None
         extruder_stacks = []
         for container_stack_file in container_stack_files:
             container_id = container_stack_file.replace("Cura/", "")
-            container_id = container_id.replace(".stack.cfg", "")
-            stack = ContainerStack(container_id)
+            container_id = container_id.replace(".%s" % container_stack_suffix, "")
 
-            # Serialize stack by converting read data from bytes to string
+            # Check if a stack by this ID already exists;
+            container_stacks = container_registry.findContainerStacks(id = container_id)
+            if container_stacks:
+                print("CONTAINER ALREADY EXISTSSS")
+
+            #stack = ContainerStack(container_id)
+
+            # Deserialize stack by converting read data from bytes to string
             stack.deserialize(archive.open(container_stack_file).read().decode("utf-8"))
 
             if stack.getMetaDataEntry("type") == "extruder_train":
                 extruder_stacks.append(stack)
             else:
-                global_stack = stack
-
-        # Check if the right machine type is active now
-        #Application.getInstance().getGlobalContainerStack().getBottom().getId() ==
-
+                global_stack = stack'''
 
         return nodes