diff --git a/meta/Parameters.m b/meta/Parameters.m
index 354767df8..4f0ff8549 100644
--- a/meta/Parameters.m
+++ b/meta/Parameters.m
@@ -307,7 +307,7 @@
                  Cases[compactExpr, SARAH`Q[a_]     /; MemberQ[parameters,SARAH`Q[a]] :> SARAH`Q[a], {0,Infinity}]
                }]];
            (* remove parameters found from compactExpr *)
-           compactExpr = compactExpr /. (RuleDelayed[#, CConversion`ToValidCSymbolString[#]]& /@ symbols);
+           compactExpr = compactExpr /. (RuleDelayed[#, Evaluate[CConversion`ToValidCSymbolString[#]]]& /@ symbols);
            (* find all parameters without SARAH head in compactExpr *)
            symbols = Join[symbols,
                { Cases[compactExpr, a_Symbol /; MemberQ[parameters,a], {0,Infinity}],
diff --git a/test/test_Parameters.m b/test/test_Parameters.m
index 941706681..e1e347ae8 100644
--- a/test/test_Parameters.m
+++ b/test/test_Parameters.m
@@ -147,6 +147,11 @@
              Sort[{SARAH`B[Mu], SARAH`Q[WOp]}]
             ];
 
+expr = Which[WOp > 1, Sqrt[B[Mu]]];
+
+TestEquality[Sort[Parameters`FindAllParameters[expr]],
+             Sort[{B[Mu], WOp}]];
+
 Print["testing GetType[] ..."];
 
 TestEquality[Parameters`GetType[x],