diff --git a/400_xowa/src/gplx/xowa/files/repos/Xof_itm_ttl_.java b/400_xowa/src/gplx/xowa/files/repos/Xof_itm_ttl_.java
index 77ca2bba1..24c57c6ca 100644
--- a/400_xowa/src/gplx/xowa/files/repos/Xof_itm_ttl_.java
+++ b/400_xowa/src/gplx/xowa/files/repos/Xof_itm_ttl_.java
@@ -26,13 +26,15 @@ public class Xof_itm_ttl_ {
 	}
 	public static byte[] Shorten(Bry_bfr bfr, byte[] ttl, int ttl_max, byte[] md5, byte[] ext_bry) {
 		byte[] rv = ttl;
-		int exceed_len = rv.length - ttl_max;
+		int exceed_len = rv.length - ttl_max;               // calc exceed_len;        EX: 21 = 201 - 180
 		if (exceed_len > 0) {
-			bfr.Add_mid(rv, 0, ttl_max - 33);		// add truncated title;		33=_.length + md5.length
-			bfr.Add_byte(Byte_ascii.Underline);		// add underline;			EX: "_"
-			bfr.Add(md5);							// add md5;					EX: "abcdefghijklmnopqrstuvwxyz0123456"
-			bfr.Add_byte(Byte_ascii.Dot);			// add dot;					EX: "."
-			bfr.Add(ext_bry);						// add ext;					EX: ".png"
+			if (ttl_max > 33) {
+				bfr.Add_mid(rv, 0, ttl_max - 33);           // add truncated title;    33=_.length + md5.length; EX: 180 - 33
+			    bfr.Add_byte(Byte_ascii.Underline);         // add underline;          EX: "_"
+			}
+			bfr.Add(md5);                                   // add md5;                EX: "abcdefghijklmnopqrstuvwxyz0123456"
+			bfr.Add_byte(Byte_ascii.Dot);                   // add dot;                EX: "."
+			bfr.Add(ext_bry);                               // add ext;                EX: ".png"
 			rv = bfr.To_bry_and_clear();
 		}
 		return rv;
diff --git a/400_xowa/src/gplx/xowa/files/repos/Xof_repo_itm.java b/400_xowa/src/gplx/xowa/files/repos/Xof_repo_itm.java
index 6dc579fbc..ffbfdc04e 100644
--- a/400_xowa/src/gplx/xowa/files/repos/Xof_repo_itm.java
+++ b/400_xowa/src/gplx/xowa/files/repos/Xof_repo_itm.java
@@ -40,6 +40,7 @@ public class Xof_repo_itm implements Gfo_invk {
 	public byte[][]			Mode_names()		{return mode_names;}	private byte[][] mode_names = new byte[][] {Xof_img_mode_.Names_ary[0], Xof_img_mode_.Names_ary[1]};
 	public Xof_rule_grp		Ext_rules()			{return ext_rules;}		private Xof_rule_grp ext_rules;
 	public boolean			Primary()			{return primary;}		private boolean primary;
+	public void             Url_max_len_(int v) {url_max_len = v;}      private int url_max_len = 250;
 
 	public Xof_repo_itm		Fsys_is_wnt_(boolean v) {fsys_is_wnt = v; return this;} 
 	public Xof_repo_itm		Shorten_ttl_(boolean v) {shorten_ttl = v; return this;} 
@@ -82,7 +83,26 @@ public class Xof_repo_itm implements Gfo_invk {
 	}
 	public byte[] Gen_name_trg(Bry_bfr tmp_bfr, byte[] bry, byte[] md5, Xof_ext ext) {
 		byte[] rv = Gen_name_src(tmp_bfr, bry);
-		return shorten_ttl ? Xof_itm_ttl_.Shorten(tmp_bfr, rv, Ttl__max_len, md5, ext.Ext()) : rv;
+		if (shorten_ttl) {
+			int max = url_max_len;
+			if (fsys_is_wnt) {
+				max = url_max_len          // 250 is approximate max of windows path
+					- root_bry.length      // EX: "C:\xowa\"
+					- 5                    // EX: "file\"
+					- 6                    // EX: "thumb\"
+					- dir_depth * 2        // EX: "0\1\2\3\"; *2  is for "\"
+					- 17                   // 17 is length of "\1234px@1234-1234"
+					- ext.Ext().length + 1 // EX: ".png"; +1 is for "."
+					;
+			}
+			else {
+				max = 180; // legacy val of max title; can probably be higher
+			}
+			return Xof_itm_ttl_.Shorten(tmp_bfr, rv, max, md5, ext.Ext());
+		}
+		else {
+			return rv;
+		}
 	}
 	public Object Invk(GfsCtx ctx, int ikey, String k, GfoMsg m) {
 		if		(ctx.Match(k, Invk_owner))				throw Err_.new_unimplemented_w_msg("deprecated repo_itm.owner");
@@ -96,5 +116,4 @@ public class Xof_repo_itm implements Gfo_invk {
 		return this;
 	}
 	private static final String Invk_owner = "owner", Invk_fsys_ = "fsys_", Invk_ext_rules_ = "ext_rules_", Invk_primary_ = "primary_", Invk_wmf_api_ = "wmf_api_", Invk_tarball_ = "tarball_", Invk_tid_ = "tid_";
-	public static final int Ttl__max_len = 180;
 }
diff --git a/400_xowa/src/gplx/xowa/files/repos/Xof_repo_itm__tst.java b/400_xowa/src/gplx/xowa/files/repos/Xof_repo_itm__tst.java
new file mode 100644
index 000000000..c249bd9f0
--- /dev/null
+++ b/400_xowa/src/gplx/xowa/files/repos/Xof_repo_itm__tst.java
@@ -0,0 +1,56 @@
+/*
+XOWA: the XOWA Offline Wiki Application
+Copyright (C) 2012-2017 gnosygnu@gmail.com
+
+XOWA is licensed under the terms of the General Public License (GPL) Version 3,
+or alternatively under the terms of the Apache License Version 2.0.
+
+You may use XOWA according to either of these licenses as is most appropriate
+for your project on a case-by-case basis.
+
+The terms of each license can be found in the source code repository:
+
+GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
+Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
+*/
+package gplx.xowa.files.repos; import gplx.*; import gplx.xowa.*; import gplx.xowa.files.*;
+import org.junit.*; import gplx.core.tests.*;
+import gplx.core.envs.*;
+import gplx.xowa.apps.fsys.*;
+import gplx.xowa.files.exts.*;
+public class Xof_repo_itm__tst {
+	private final    Xof_repo_itm__fxt fxt = new Xof_repo_itm__fxt();
+	@Test 	public void Gen_name_trg__long() {
+		// make a windows repo with a long directory name
+		Xof_repo_itm repo = fxt.Make__repo(Op_sys.Wnt.Os_name(), "C:\\xowa0123456789", "commons.wikimedia.org");
+
+		// mark it as wnt repo and reduce max ttl_len from 160 to 99 for shorter test vars
+		repo.Fsys_is_wnt_(true).Url_max_len_(99);
+
+		// short: full name
+		fxt.Test__gen_name_trg(repo, "A.png", "A.png");
+
+		// long: truncated_ttl + md5
+		fxt.Test__gen_name_trg(repo, "0123456789012345678901234567890123456789.png", "0123456789_965d037bf686058361510201be299ed4.png");
+
+		// extremely long; md5 only
+		repo.Root_str_("C:\\xowa012345678901234567890123456789");
+		fxt.Test__gen_name_trg(repo, "0123456789012345678901234567890123456789.png", "965d037bf686058361510201be299ed4.png");
+	}
+}
+class Xof_repo_itm__fxt {
+	private final    Bry_bfr tmp_bfr = Bry_bfr_.New();
+	public Xof_repo_itm Make__repo(String plat_name, String root_dir_str, String wiki_domain) {
+		String key = "test_repo";
+		Io_url root_dir = Io_url_.new_dir_(root_dir_str);
+		Xoa_fsys_mgr fsys_mgr = new Xoa_fsys_mgr(plat_name, root_dir, root_dir.GenSubDir("wiki"), root_dir.GenSubDir("file"), root_dir.GenSubDir("css"), root_dir.GenSubDir("html"));
+		Xof_repo_itm repo = new Xof_repo_itm(Bry_.new_u8(key), fsys_mgr, new Xof_rule_mgr(), Bry_.new_u8(wiki_domain));
+		repo.Root_str_(root_dir.Raw());
+		return repo;
+	}
+	public void Test__gen_name_trg(Xof_repo_itm repo, String ttl_str, String expd) {
+		byte[] ttl_bry = Bry_.new_u8(ttl_str);
+		byte[] md5 = Xof_file_wkr_.Md5(ttl_bry);
+		Gftest.Eq__str(expd, repo.Gen_name_trg(tmp_bfr, ttl_bry, md5, Xof_ext_.new_by_ttl_(ttl_bry)));
+	}
+}