diff --git a/tags/tags.legacy.tf b/tags/tags.legacy.tf
index f7b3c5e..4168fcb 100644
--- a/tags/tags.legacy.tf
+++ b/tags/tags.legacy.tf
@@ -16,7 +16,7 @@ resource "terraform_data" "legacy_finops_number" {
 
   lifecycle {
     precondition {
-      condition     = length(regexall("^fs\d{10}$",lookup(local.legacy_finops_converted,"project_number",null))) == 0
+      condition     = length(regexall("^fs\\d{10}$",lookup(local.legacy_finops_converted,"project_number",null))) == 0
       error_message = "Invalid legacy finops project_number format."
     }
   }