diff --git a/products/models.py b/products/models.py
index 81f5146..0b83afa 100644
--- a/products/models.py
+++ b/products/models.py
@@ -18,7 +18,6 @@ class CategoryTag(TagTreeModel):
     class TagMeta:
         initial = ""
         force_lowercase = True
-        max_count=20
         # autocomplete_view = 'myapp.views.hobbies_autocomplete'
 
 
@@ -58,15 +57,15 @@ class Product(models.Model):
     discount = models.DecimalField('Descuento', max_digits=5, decimal_places=2, null=True, blank=True)
     stock = models.PositiveIntegerField('Stock', null=True, blank=True)
     tags = TagField(to=TreeTag)
-    category = SingleTagField(to=CategoryTag, null=True, blank=True) # main tag category
+    category = SingleTagField(to=CategoryTag, null=True, blank=True, on_delete=models.SET_NULL) # main tag category
     attributes = TagField(to=AttributeTag, related_name='product_attributes')
     identifiers = models.TextField('Identificador único de producto', null=True, blank=True)
 
     # internal
     created = models.DateTimeField('date of creation', auto_now_add=True)
     updated = models.DateTimeField('date last update', auto_now=True)
-    creator = models.ForeignKey('core.CustomUser', on_delete=models.DO_NOTHING, null=True, related_name='product')
-    history = models.ForeignKey('history.HistorySync', on_delete=models.DO_NOTHING, null=True, related_name='product')
+    creator = models.ForeignKey('core.CustomUser', on_delete=models.SET_NULL, null=True, related_name='product')
+    history = models.ForeignKey('history.HistorySync', on_delete=models.SET_NULL, null=True, related_name='product')
 
     def __str__(self):
         return f"{self.name} / {self.sku}"