diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -26,3 +26,8 @@
 ## 0.3.2.0 -- 2020-11-28
 
 * Third version revised B. Some code improvements. Changed the maximumGroupsClassificationR arguments.
+
+## 0.3.3.0 -- 2020-11-28
+
+* Third version revised C. Fixed issue with group classification for empty data.
+
diff --git a/Phonetic/Languages/Simplified/DataG.hs b/Phonetic/Languages/Simplified/DataG.hs
--- a/Phonetic/Languages/Simplified/DataG.hs
+++ b/Phonetic/Languages/Simplified/DataG.hs
@@ -83,6 +83,7 @@
   -> (t2 (t a), t2 (t a))
   -> (t2 (t a), t2 (t a))
 maximumGroupsClassification !nGroups !frep2 (dataT,dataF)
+ | F.null dataF = (dataT,mempty)
  | nGroups <= 0 = (dataT,dataF)
  | otherwise = maximumGroupsClassification (nGroups - 1) frep2 (dataT `mappend` partT,partF)
      where (!partT,!partF) = innerPartitioning frep2 dataF
@@ -93,6 +94,7 @@
   -> t2 (t a)
   -> (t2 (t a), t2 (t a))
 maximumGroupsClassification1 !nGroups !frep2 data0
+ | F.null data0 = (mempty,mempty)
  | nGroups <= 0 = innerPartitioning frep2 data0
  | otherwise = maximumGroupsClassification (nGroups - 1) frep2 . innerPartitioning frep2 $ data0
 
@@ -101,6 +103,7 @@
   -> t2 (Result t a b c)
   -> (t2 (Result t a b c), t2 (Result t a b c))
 maximumGroupsClassificationR !nGroups dataR
+ | F.null dataR = (mempty,mempty)
  | nGroups <= 1 = (partT,partF)
  | otherwise = (partT `mappend` (fst . maximumGroupsClassificationR (nGroups - 1) $ partF),snd . maximumGroupsClassificationR (nGroups - 1) $ partF)
      where !maxE0 = F.maximum . mapG transMetrices $ dataR
diff --git a/phonetic-languages-simplified-common.cabal b/phonetic-languages-simplified-common.cabal
--- a/phonetic-languages-simplified-common.cabal
+++ b/phonetic-languages-simplified-common.cabal
@@ -3,7 +3,7 @@
 -- http://haskell.org/cabal/users-guide/
 
 name:                phonetic-languages-simplified-common
-version:             0.3.2.0
+version:             0.3.3.0
 synopsis:            A simplified version of the phonetic-languages-functionality
 description:         A simplified version of the phonetic-languages-functionality. Tries to use only necessary functionality and reduce the other one.
 homepage:            https://hackage.haskell.org/package/phonetic-languages-simlified-common