diff --git a/builder/downloader.ml b/builder/downloader.ml
index 3e776fdc2..b1119bae4 100644
--- a/builder/downloader.ml
+++ b/builder/downloader.ml
@@ -68,7 +68,7 @@ let rec download t ?template ?progress_bar ?(proxy = Curl.SystemProxy) uri =
 and download_to t ?(progress_bar = false) ~proxy uri filename =
   let parseduri =
     try URI.parse_uri uri
-    with Invalid_argument "URI.parse_uri" ->
+    with URI.Parse_failed ->
       error (f_"error parsing URI '%s'. Look for error messages printed above.")
         uri in
 
diff --git a/builder/sources.ml b/builder/sources.ml
index 93609bef6..d6de15968 100644
--- a/builder/sources.ml
+++ b/builder/sources.ml
@@ -51,7 +51,7 @@ let parse_conf file =
           let k =
             try Some (URI.parse_uri (List.assoc ("gpgkey", None) fields)) with
             | Not_found -> None
-            | Invalid_argument "URI.parse_uri" as ex ->
+            | URI.Parse_failed as ex ->
                debug "'%s' has invalid gpgkey URI" n;
                raise ex in
           match k with
diff --git a/common/mltools/URI.ml b/common/mltools/URI.ml
index c143ae2b9..0f51b612b 100644
--- a/common/mltools/URI.ml
+++ b/common/mltools/URI.ml
@@ -24,4 +24,9 @@ type uri = {
   password : string option;
 }
 
+exception Parse_failed
+
 external parse_uri : string -> uri = "guestfs_int_mllib_parse_uri"
+
+let () =
+  Callback.register_exception "URI.Parse_failed" Parse_failed
diff --git a/common/mltools/URI.mli b/common/mltools/URI.mli
index 0692f955f..1ef941268 100644
--- a/common/mltools/URI.mli
+++ b/common/mltools/URI.mli
@@ -26,5 +26,13 @@ type uri = {
   password : string option;             (** password *)
 }
 
+exception Parse_failed
+
 val parse_uri : string -> uri
-(** See [fish/uri.h]. *)
+(** See [fish/uri.h].
+
+    This can raise {!Parse_failed}.
+
+    Unfortunately we cannot be specific about the actual error
+    (although [fish/uri.c] should print something).  XXX We should
+    be able to fetch and throw a real exception with the error. *)
diff --git a/common/mltools/uri-c.c b/common/mltools/uri-c.c
index 3e539c50e..b068c2960 100644
--- a/common/mltools/uri-c.c
+++ b/common/mltools/uri-c.c
@@ -26,6 +26,7 @@
 #include <locale.h>
 
 #include <caml/alloc.h>
+#include <caml/callback.h>
 #include <caml/fail.h>
 #include <caml/memory.h>
 #include <caml/mlvalues.h>
@@ -45,8 +46,10 @@ guestfs_int_mllib_parse_uri (value argv /* arg value, not an array! */)
   int r;
 
   r = parse_uri (String_val (argv), &uri);
-  if (r == -1)
-    caml_invalid_argument ("URI.parse_uri");
+  if (r == -1) {
+    value *exn = caml_named_value ("URI.Parse_failed");
+    caml_raise (*exn);
+  }
 
   /* Convert the struct into an OCaml tuple. */
   rv = caml_alloc_tuple (5);
diff --git a/customize/customize_main.ml b/customize/customize_main.ml
index aad6ebe65..8bd197b83 100644
--- a/customize/customize_main.ml
+++ b/customize/customize_main.ml
@@ -59,7 +59,7 @@ let main () =
   let add_file arg =
     let uri =
       try URI.parse_uri arg
-      with Invalid_argument "URI.parse_uri" ->
+      with URI.Parse_failed ->
         error (f_"error parsing URI '%s'. Look for error messages printed above.")
           arg in
     let format = match !format with "auto" -> None | fmt -> Some fmt in
diff --git a/get-kernel/get_kernel.ml b/get-kernel/get_kernel.ml
index 03e1a13c1..10ead853f 100644
--- a/get-kernel/get_kernel.ml
+++ b/get-kernel/get_kernel.ml
@@ -40,7 +40,7 @@ let parse_cmdline () =
       error (f_"--add option can only be given once");
     let uri =
       try URI.parse_uri arg
-      with Invalid_argument "URI.parse_uri" ->
+      with URI.Parse_failed ->
         error (f_"error parsing URI '%s'. Look for error messages printed above.") arg in
     file := Some uri
   and set_domain dom =
diff --git a/resize/resize.ml b/resize/resize.ml
index 49fdfd538..f428f3ebe 100644
--- a/resize/resize.ml
+++ b/resize/resize.ml
@@ -313,14 +313,14 @@ read the man page virt-resize(1).
     (* infile can be a URI. *)
     let infile =
       try (infile, URI.parse_uri infile)
-      with Invalid_argument "URI.parse_uri" ->
+      with URI.Parse_failed ->
         error (f_"error parsing URI ‘%s’. Look for error messages printed above.")
           infile in
 
     (* outfile can be a URI. *)
     let outfile =
       try (outfile, URI.parse_uri outfile)
-      with Invalid_argument "URI.parse_uri" ->
+      with URI.Parse_failed ->
         error (f_"error parsing URI ‘%s’. Look for error messages printed above.")
           outfile in
 
diff --git a/sysprep/main.ml b/sysprep/main.ml
index 75aba578b..3ba0c7b82 100644
--- a/sysprep/main.ml
+++ b/sysprep/main.ml
@@ -55,7 +55,7 @@ let main () =
     let add_file arg =
       let uri =
         try URI.parse_uri arg
-        with Invalid_argument "URI.parse_uri" ->
+        with URI.Parse_failed ->
           error (f_"error parsing URI ‘%s’. Look for error messages printed above.") arg in
       let format = match !format with "auto" -> None | fmt -> Some fmt in
       push_front (uri, format) files;