diff --git a/crc.cpp b/crc.cpp
index 0ddfe448..77a21ca9 100644
--- a/crc.cpp
+++ b/crc.cpp
@@ -124,12 +124,12 @@ CRC32::CRC32()
 
 void CRC32::Update(const byte *s, size_t n)
 {
-	assert(IsAlignedOn(s,GetAlignmentOf<word32>()));
 	word32 crc = m_crc;
 
 	for(; !IsAligned<word32>(s) && n > 0; n--)
 		crc = m_tab[CRC32_INDEX(crc) ^ *s++] ^ CRC32_SHIFTED(crc);
 
+	assert((n && IsAlignedOn(s,GetAlignmentOf<word32>())) || !n);
 	while (n >= 4)
 	{
 		crc ^= *(const word32 *)(void*)s;