diff --git a/pkgs/servers/dns/knot-dns/default.nix b/pkgs/servers/dns/knot-dns/default.nix
index de37aeaa590..88fa07009f8 100644
--- a/pkgs/servers/dns/knot-dns/default.nix
+++ b/pkgs/servers/dns/knot-dns/default.nix
@@ -32,7 +32,7 @@ stdenv.mkDerivation rec {
 
   #doCheck = true; problems in combination with dynamic linking
 
-  postInstall = ''rm -r "$out"/var'';
+  postInstall = ''rm -r "$out"/var "$out"/lib/*.la'';
 
   meta = with stdenv.lib; {
     description = "Authoritative-only DNS server from .cz domain registry";