diff --git a/common/error_code.h b/common/error_code.h
index 7d9cfff..a889888 100644
--- a/common/error_code.h
+++ b/common/error_code.h
@@ -86,6 +86,7 @@
   kNotEnoughSpace = 60,
   kDeviceCorrupted = 61,
   kPackageExcludedFromUpdate = 62,
+  kPostInstallMountError = 63,
 
   // VERY IMPORTANT! When adding new error codes:
   //
diff --git a/common/error_code_utils.cc b/common/error_code_utils.cc
index cda4c7e..421544a 100644
--- a/common/error_code_utils.cc
+++ b/common/error_code_utils.cc
@@ -173,6 +173,8 @@
       return "ErrorCode::kDeviceCorrupted";
     case ErrorCode::kPackageExcludedFromUpdate:
       return "ErrorCode::kPackageExcludedFromUpdate";
+    case ErrorCode::kPostInstallMountError:
+      return "ErrorCode::kPostInstallMountError";
       // Don't add a default case to let the compiler warn about newly added
       // error codes which should be added here.
   }