diff --git a/erpnext/projects/doctype/project/project.py b/erpnext/projects/doctype/project/project.py
index bc4e4d869c0..f382118042a 100644
--- a/erpnext/projects/doctype/project/project.py
+++ b/erpnext/projects/doctype/project/project.py
@@ -364,13 +364,18 @@ class Project(Document):
 		)
 
 		for user in self.users:
+			# process only users who haven't received the welcome email yet
 			if user.welcome_email_sent == 0:
-				frappe.sendmail(
-					user.user,
-					subject=_("Project Collaboration Invitation"),
-					content=content,
-				)
-				user.welcome_email_sent = 1
+				# fetch canonical User data (enabled status + latest email)
+				user_info = frappe.db.get_value("User", user.user, ["enabled", "email"], as_dict=True)
+				# send email only if user is enabled and has a valid email
+				if user_info and user_info.enabled and user_info.email:
+					frappe.sendmail(
+						recipients=[user_info.email],
+						subject=_("Project Collaboration Invitation"),
+						content=content,
+					)
+					user.welcome_email_sent = 1
 
 
 def get_timeline_data(doctype: str, name: str) -> dict[int, int]: