diff --git a/specifyweb/backend/businessrules/rules/collectionobject_rules.py b/specifyweb/backend/businessrules/rules/collectionobject_rules.py
index 40ffec39a0c..3d84088b567 100644
--- a/specifyweb/backend/businessrules/rules/collectionobject_rules.py
+++ b/specifyweb/backend/businessrules/rules/collectionobject_rules.py
@@ -2,6 +2,7 @@
 
 from specifyweb.backend.businessrules.exceptions import BusinessRuleException
 from specifyweb.backend.businessrules.utils import get_unique_catnum_across_comp_co_coll_pref
+from specifyweb.specify.api.utils import get_or_create_default_collection_object_type
 from specifyweb.specify.models import Component
 
 
@@ -10,8 +11,15 @@ def collectionobject_pre_save(co):
     if co.collectionmemberid is None:
         co.collectionmemberid = co.collection_id
 
-    if co.collectionobjecttype is None: 
-        co.collectionobjecttype = co.collection.collectionobjecttype
+    if co.collectionobjecttype is None:
+        if co.collection.collectionobjecttype is not None:
+            co.collectionobjecttype = co.collection.collectionobjecttype
+        elif co.pk is not None:
+            co.collectionobjecttype = (
+                get_or_create_default_collection_object_type(
+                    co.collection, using=co._state.db or 'default'
+                )
+            )
 
     agent = co.createdbyagent
     if agent is not None and agent.specifyuser is not None:
@@ -25,4 +33,4 @@ def collectionobject_pre_save(co):
 
                 if contains_component_duplicates: 
                     raise BusinessRuleException(
-                        'Catalog Number is already in use for another Component in this collection.')
\ No newline at end of file
+                        'Catalog Number is already in use for another Component in this collection.')
diff --git a/specifyweb/frontend/js_src/lib/components/DataModel/__tests__/businessRules.test.ts b/specifyweb/frontend/js_src/lib/components/DataModel/__tests__/businessRules.test.ts
index 26226f396f9..1ef80c1e81d 100644
--- a/specifyweb/frontend/js_src/lib/components/DataModel/__tests__/businessRules.test.ts
+++ b/specifyweb/frontend/js_src/lib/components/DataModel/__tests__/businessRules.test.ts
@@ -194,6 +194,64 @@ describe('Collection Object business rules', () => {
       expect(result.current[0]).toStrictEqual([]);
     });
 
+    test('CollectionObject -> determinations: Save is not blocked when collection object type is missing', async () => {
+      const collectionObject = getBaseCollectionObject();
+      collectionObject.set('collectionObjectType', null as never, {
+        silent: true,
+      });
+
+      const determination =
+        collectionObject.getDependentResource('determinations')?.models[0];
+
+      const { result } = renderHook(() =>
+        useSaveBlockers(determination, tables.Determination.getField('Taxon'))
+      );
+
+      await act(async () => {
+        await collectionObject?.businessRuleManager?.checkField(
+          'collectionObjectType'
+        );
+      });
+
+      expect(result.current[0]).toStrictEqual([]);
+    });
+
+    test('CollectionObject -> determinations: Missing collection object type clears invalid determination blockers', async () => {
+      const collectionObject = getBaseCollectionObject();
+      collectionObject.set(
+        'collectionObjectType',
+        getResourceApiUrl('CollectionObjectType', 1)
+      );
+
+      const determination =
+        collectionObject.getDependentResource('determinations')?.models[0];
+
+      const { result } = renderHook(() =>
+        useSaveBlockers(determination, tables.Determination.getField('Taxon'))
+      );
+
+      await act(async () => {
+        await collectionObject?.businessRuleManager?.checkField(
+          'collectionObjectType'
+        );
+      });
+      expect(result.current[0]).toStrictEqual([
+        resourcesText.invalidDeterminationTaxon(),
+      ]);
+
+      collectionObject.set('collectionObjectType', null as never, {
+        silent: true,
+      });
+
+      await act(async () => {
+        await collectionObject?.businessRuleManager?.checkField(
+          'collectionObjectType'
+        );
+      });
+
+      expect(result.current[0]).toStrictEqual([]);
+    });
+
     test('Newly added determinations are current by default', async () => {
       const collectionObject = getBaseCollectionObject();
       const determinations =
diff --git a/specifyweb/frontend/js_src/lib/components/DataModel/businessRuleDefs.ts b/specifyweb/frontend/js_src/lib/components/DataModel/businessRuleDefs.ts
index 5b0fe4fe7d0..d6542338da6 100644
--- a/specifyweb/frontend/js_src/lib/components/DataModel/businessRuleDefs.ts
+++ b/specifyweb/frontend/js_src/lib/components/DataModel/businessRuleDefs.ts
@@ -181,6 +181,19 @@ export const businessRuleDefs: MappedBusinessRuleDefs = {
           determinations.models.map(async (det) => det.rgetPromise('taxon'))
         );
         const coType = await resource.rgetPromise('collectionObjectType');
+
+        if (coType === null) {
+          determinations.models.forEach((determination) => {
+            setSaveBlockers(
+              determination,
+              determination.specifyTable.field.taxon,
+              [],
+              DETERMINATION_TAXON_KEY
+            );
+          });
+          return;
+        }
+
         const coTypeTreeDef = coType.get('taxonTreeDef');
 
         // Block save when a Determination -> Taxon does not belong to the COType's tree definition
diff --git a/specifyweb/specify/api/utils.py b/specifyweb/specify/api/utils.py
index 1b53ff42bd7..75fdde50871 100644
--- a/specifyweb/specify/api/utils.py
+++ b/specifyweb/specify/api/utils.py
@@ -29,6 +29,32 @@ def log_sqlalchemy_query(query):
     # Run in the storred_queries.execute file, in the execute function, right before the return statement, line 546
     # from specifyweb.specify.utils import log_sqlalchemy_query; log_sqlalchemy_query(query)
 
+def get_or_create_default_collection_object_type(collection: spmodels.Collection, using: str = "default"):
+    db = using or "default"
+
+    if collection.collectionobjecttype is not None:
+        return collection.collectionobjecttype
+
+    discipline_name = collection.discipline.name
+    taxon_tree_def_id = collection.discipline.taxontreedef_id
+
+    if discipline_name is None or taxon_tree_def_id is None:
+        return None
+
+    default_type, _ = spmodels.Collectionobjecttype.objects.using(db).get_or_create(
+        name=discipline_name,
+        collection=collection,
+        taxontreedef_id=taxon_tree_def_id,
+    )
+
+    type(collection).objects.using(db).filter(
+        pk=collection.pk,
+        collectionobjecttype__isnull=True,
+    ).update(collectionobjecttype=default_type)
+    collection.collectionobjecttype = default_type
+
+    return default_type
+
 def create_default_collection_types(apps, using="default"):
     db = using or "default"
 
@@ -90,4 +116,4 @@ def get_picklists(collection: spmodels.Collection, tablename: str, fieldname: st
         if len(collection_picklists) > 0:
             picklists = collection_picklists
 
-    return picklists, schemaitem
\ No newline at end of file
+    return picklists, schemaitem