diff --git a/src/liblzma/common/alone_decoder.c b/src/liblzma/common/alone_decoder.c
index e850a926..c822f04c 100644
--- a/src/liblzma/common/alone_decoder.c
+++ b/src/liblzma/common/alone_decoder.c
@@ -214,6 +214,8 @@ lzma_alone_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
 	next->coder->sequence = SEQ_PROPERTIES;
 	next->coder->pos = 0;
 	next->coder->options.dict_size = 0;
+	next->coder->options.preset_dict = NULL;
+	next->coder->options.preset_dict_size = 0;
 	next->coder->uncompressed_size = 0;
 	next->coder->memlimit = memlimit;
 	next->coder->memusage = LZMA_MEMUSAGE_BASE;