diff --git a/sys/fs/nfsclient/nfs_clstate.c b/sys/fs/nfsclient/nfs_clstate.c
index 0a2e4bc7e82..4a7df72dfa7 100644
--- a/sys/fs/nfsclient/nfs_clstate.c
+++ b/sys/fs/nfsclient/nfs_clstate.c
@@ -3188,8 +3188,11 @@ lookformore:
 			    !NFSBCMP(op->nfso_fh, nfhp->nfh_fh,
 			    nfhp->nfh_len)) {
 				/* Found an open, close it. */
+#ifdef DIAGNOSTIC
 				KASSERT((op->nfso_opencnt == 0),
-				    ("nfscl: bad open cnt on server"));
+				    ("nfscl: bad open cnt on server (%d)",
+				     op->nfso_opencnt));
+#endif
 				NFSUNLOCKCLSTATE();
 				nfsrpc_doclose(VFSTONFS(vnode_mount(vp)), op,
 				    p);