diff --git a/NEWS b/NEWS
index 244e123f..a05c1259 100644
--- a/NEWS
+++ b/NEWS
@@ -1,5 +1,16 @@
 xbps-0.38 (???):
 
+ * libxbps: return ENXIO and a meaningful error message if a package that is
+   going to be installed or updated has invalid dependencies, i.e:
+
+	$ xbps-install --repository=$HOME/repo -n foo
+	ERROR: foo-1.0_1: can't guess pkgname for dependency '>=invalid-spec_1'
+	Package `foo' contains invalid dependencies, exiting.
+	$
+
+   This fixes #43 (xbps-install: unhelpful message for invalid dependency)
+   submitted by Dominik Honnef.
+
  * libxbps: fixed a new issue with packages that provide/replace the
    same virtual package that is going to be replaced. The issue could be
    reproduced easily by installing any awk package (gawk, mawk, or nawk),
diff --git a/bin/xbps-install/state_cb.c b/bin/xbps-install/state_cb.c
index ba9accd3..d0aeb09c 100644
--- a/bin/xbps-install/state_cb.c
+++ b/bin/xbps-install/state_cb.c
@@ -159,8 +159,12 @@ state_cb(struct xbps_state_cb_data *xscd, void *cbdata _unused)
 		}
 		break;
 	default:
-		xbps_dbg_printf(xscd->xhp,
-		    "%s: unknown state %d\n", xscd->arg, xscd->state);
+		if (xscd->desc)
+			xbps_error_printf("%s\n", xscd->desc);
+		else
+			xbps_dbg_printf(xscd->xhp,
+			    "%s: unknown state %d\n", xscd->arg, xscd->state);
+
 		break;
 	}
 
diff --git a/bin/xbps-install/transaction.c b/bin/xbps-install/transaction.c
index 453bb13b..76429f59 100644
--- a/bin/xbps-install/transaction.c
+++ b/bin/xbps-install/transaction.c
@@ -224,6 +224,8 @@ install_new_pkg(struct xbps_handle *xhp, const char *pkg, bool reinstall)
 		} else if (rv == ENOTSUP) {
 			fprintf(stderr, "No repositories  "
 			    "currently registered!\n");
+		} else if (rv == ENXIO) {
+			fprintf(stderr, "Package `%s' contains invalid dependencies, exiting.\n", pkg);
 		} else {
 			fprintf(stderr, "Unexpected error: %s\n",
 			    strerror(rv));
diff --git a/include/xbps.h.in b/include/xbps.h.in
index f4d88cba..cb67d323 100644
--- a/include/xbps.h.in
+++ b/include/xbps.h.in
@@ -48,7 +48,7 @@
  *
  * This header documents the full API for the XBPS Library.
  */
-#define XBPS_API_VERSION	"20140604"
+#define XBPS_API_VERSION	"20140702"
 
 #ifndef XBPS_VERSION
  #define XBPS_VERSION		"UNSET"
@@ -275,6 +275,7 @@ extern "C" {
  * - XBPS_STATE_UNPACK_FAIL: package unpack has failed.
  * - XBPS_STATE_REPOSYNC_FAIL: syncing remote repositories has failed.
  * - XBPS_STATE_REPO_KEY_IMPORT: repository is signed and needs to import pubkey.
+ * - XBPS_STATE_INVALID_DEP: package has an invalid dependency.
  */
 typedef enum xbps_state {
 	XBPS_STATE_UNKNOWN = 0,
@@ -313,7 +314,8 @@ typedef enum xbps_state {
 	XBPS_STATE_UNPACK_FAIL,
 	XBPS_STATE_REPOSYNC_FAIL,
 	XBPS_STATE_CONFIGURE_DONE,
-	XBPS_STATE_REPO_KEY_IMPORT
+	XBPS_STATE_REPO_KEY_IMPORT,
+	XBPS_STATE_INVALID_DEP
 } xbps_state_t;
 
 /**
@@ -1035,6 +1037,7 @@ xbps_object_iterator_t xbps_array_iter_from_dict(xbps_dictionary_t dict,
  * @retval EEXIST Package is already installed (reinstall wasn't enabled).
  * @retval ENOENT Package not matched in repository pool.
  * @retval ENOTSUP No repositories are available.
+ * @retval ENXIO Package depends on invalid dependencies.
  * @retval EINVAL Any other error ocurred in the process.
  */
 int xbps_transaction_install_pkg(struct xbps_handle *xhp,
@@ -1051,6 +1054,11 @@ int xbps_transaction_install_pkg(struct xbps_handle *xhp,
  * @param[in] pkgname The package name to update.
  *
  * @return 0 on success, otherwise an errno value.
+ * @retval EEXIST Package is already up-to-date.
+ * @retval ENOENT Package not matched in repository pool.
+ * @retval ENOTSUP No repositories are available.
+ * @retval ENXIO Package depends on invalid dependencies.
+ * @retval EINVAL Any other error ocurred in the process.
  */
 int xbps_transaction_update_pkg(struct xbps_handle *xhp, const char *pkgname);
 
@@ -1060,7 +1068,9 @@ int xbps_transaction_update_pkg(struct xbps_handle *xhp, const char *pkgname);
  * into the transaction dictionary.
  *
  * @param[in] xhp Pointer to the xbps_handle struct.
+ *
  * @return 0 on success, otherwise an errno value.
+ * @retval EEXIST All installed package are already up-to-date.
  */
 int xbps_transaction_update_packages(struct xbps_handle *xhp);
 
diff --git a/lib/repo_pkgdeps.c b/lib/repo_pkgdeps.c
index 7a56b104..ca08d169 100644
--- a/lib/repo_pkgdeps.c
+++ b/lib/repo_pkgdeps.c
@@ -187,8 +187,10 @@ find_repo_deps(struct xbps_handle *xhp,
 		}
 		if (((pkgname = xbps_pkgpattern_name(reqpkg)) == NULL) &&
 		    ((pkgname = xbps_pkg_name(reqpkg)) == NULL)) {
-			xbps_dbg_printf(xhp, "can't guess pkgname for %s\n", reqpkg);
-			rv = EINVAL;
+			xbps_dbg_printf(xhp, "%s: can't guess pkgname for dependency: %s\n", curpkg, reqpkg);
+			xbps_set_cb_state(xhp, XBPS_STATE_INVALID_DEP, ENXIO, NULL,
+			    "%s: can't guess pkgname for dependency '%s'", curpkg, reqpkg);
+			rv = ENXIO;
 			break;
 		}
 		/*