--- a/doc/book/en/annexes/faq.rst	Tue Sep 28 14:52:45 2010 +0200
+++ b/doc/book/en/annexes/faq.rst	Tue Sep 28 16:50:34 2010 +0200
@@ -408,6 +408,11 @@
 
     update cw_cwuser set cw_upassword=CONVERT(varbinary(255), 'qHO8282QN5Utg') where cw_login='joe';
 
+Be careful, the encryption algorithm is different on Windows and on
+Unix. You cannot therefore use a hash generated on Unix to fill in a
+Windows database, nor the other way round. 
+
+
 You can prefer use a migration script similar to this shell invocation instead::
 
     $ cubicweb-ctl shell <instance>