diff --git a/prover/lib/compressor/libdecompressor/libdecompressor.go b/prover/lib/compressor/libdecompressor/libdecompressor.go
index 585fc300d..4c29dc2da 100644
--- a/prover/lib/compressor/libdecompressor/libdecompressor.go
+++ b/prover/lib/compressor/libdecompressor/libdecompressor.go
@@ -25,7 +25,9 @@ var (
 //
 //export Init
 func Init() {
+	lock.Lock()
 	dictStore = dictionary.NewStore()
+	lock.Unlock()
 }
 
 // LoadDictionaries loads a number of dictionaries into the decompressor