diff --git a/ChangeLog.txt b/ChangeLog.txt
index ead178b..91eb80d 100644
--- a/ChangeLog.txt
+++ b/ChangeLog.txt
@@ -1,3 +1,12 @@
+029.  2022-12-03 20:41:17 v1.2.6
+
+    Fix a bug in formatRepMat which returns Indeterminate:
+      (-1+I)/4*((2+2*I)*(-1)^(11/12)+I*Sqrt[2]+Sqrt[6])//formatRepMat
+    An example affected by this is the following MSGCorep function:
+      showMLGCorep[{222, 100},{-1/3,2/3,1/4},"trace"->True]
+    The reason is that Simplify can not simplify the above number which is indeed 0.
+    Just change the Simplify in formatRepMat to FullSimplify to fix it.
+
 028.  2022-11-25 22:42:44 v1.2.5
 
     Add a function showBandRep to show the result of getBandRep.
diff --git a/SpaceGroupIrep.wl b/SpaceGroupIrep.wl
index eb80f9f..a1d1b29 100644
--- a/SpaceGroupIrep.wl
+++ b/SpaceGroupIrep.wl
@@ -10,7 +10,7 @@
 (* Mathematica version: >=11.2 *)
 (* License: GPLv3 http://www.gnu.org/licenses/gpl-3.0.txt *)
 
-SpaceGroupIrep`Private`Version={1,2,5};  (*Specify version here.*)
+SpaceGroupIrep`Private`Version={1,2,6};  (*Specify version here.*)
 
 With[{p=DirectoryName[$InputFileName]}, If[!MemberQ[$Path,p],AppendTo[$Path, p]]];
 
@@ -4200,7 +4200,7 @@ formatRepMat[mat_]:=Module[{norm,arg,fl,pu,poth,num},
   If[MachineNumberQ[mat], Return[Round[mat,1.*^-6]]];
   num=formatRepMatDict[mat];
   If[num=!=None, Return[num]];
-  num=Simplify[mat];
+  num=FullSimplify[mat];
   If[Flatten[Position[num,#]&/@{t\:2081,t\:2082,t\:2083}]!={}, formatRepMatDict[mat]=num; Return[num]];
   If[Position[num,u]=={}, 
     norm=Norm[num]//FullSimplify;   arg=Arg[num]//FullSimplify;