diff --git a/content/content.c b/content/content.c
index 2c7f5d00e..253caea16 100644
--- a/content/content.c
+++ b/content/content.c
@@ -121,6 +121,7 @@ struct content * content_create(char *url)
 	c->url = xstrdup(url);
 	c->type = CONTENT_UNKNOWN;
 	c->status = CONTENT_STATUS_TYPE_UNKNOWN;
+	c->cache = 0;
 	c->size = sizeof(struct content);
 	c->fetch = 0;
 	strcpy(c->status_message, "Loading");
@@ -178,6 +179,8 @@ void content_convert(struct content *c, unsigned long width, unsigned long heigh
 	if (handler_map[c->type].convert(c, width, height)) {
 		/* convert failed, destroy content */
 		content_broadcast(c, CONTENT_MSG_ERROR, "Conversion failed");
+		if (c->cache)
+			cache_destroy(c);
 		content_destroy(c);
 		return;
 	}
@@ -305,10 +308,13 @@ void content_remove_user(struct content *c,
 		if (c->fetch != 0)
 			fetch_abort(c->fetch);
 		if (c->status < CONTENT_STATUS_READY) {
-			cache_destroy(c);
+			if (c->cache)
+				cache_destroy(c);
 			content_destroy(c);
-		} else
-			cache_freeable(c);
+		} else {
+			if (c->cache)
+				cache_freeable(c);
+		}
 	}
 }
 
diff --git a/content/fetch.c b/content/fetch.c
index 3b057c266..330f68d3b 100644
--- a/content/fetch.c
+++ b/content/fetch.c
@@ -119,7 +119,10 @@ struct fetch * fetch_start(char *url, char *referer,
 	LOG(("fetch %p, url '%s'", fetch, url));
 
 	uri = xmlParseURI(url);
-	assert(uri != 0);
+	if (uri == 0) {
+		LOG(("warning: failed to parse url"));
+		return 0;
+	}
 
 	/* construct a new fetch structure */
 	fetch->start_time = time(0);
diff --git a/content/fetchcache.c b/content/fetchcache.c
index 844111376..99686efe0 100644
--- a/content/fetchcache.c
+++ b/content/fetchcache.c
@@ -46,6 +46,12 @@ struct content * fetchcache(const char *url0, char *referer,
 	c->width = width;
 	c->height = height;
 	c->fetch = fetch_start(url, referer, fetchcache_callback, c);
+	if (c->fetch == 0) {
+		LOG(("warning: fetch_start failed"));
+		cache_destroy(c);
+		content_destroy(c);
+		return 0;
+	}
 	return c;
 }
 
diff --git a/css/css.c b/css/css.c
index 8a29abb85..c894f6678 100644
--- a/css/css.c
+++ b/css/css.c
@@ -147,6 +147,8 @@ void css_revive(struct content *c, unsigned int width, unsigned int height)
 				c->data.css.import_url[i], c->url,
 				css_atimport_callback, c, i,
 				c->width, c->height);
+		if (c->data.css.import_content[i] == 0)
+			continue;
 		if (c->data.css.import_content[i]->status != CONTENT_STATUS_DONE)
 			c->active++;
 	}
@@ -296,7 +298,8 @@ void css_atimport(struct content *c, struct node *node)
 	c->data.css.import_content[i] = fetchcache(
 			c->data.css.import_url[i], c->url, css_atimport_callback,
 			c, i, c->width, c->height);
-	if (c->data.css.import_content[i]->status != CONTENT_STATUS_DONE)
+	if (c->data.css.import_content[i] &&
+			c->data.css.import_content[i]->status != CONTENT_STATUS_DONE)
 		c->active++;
 
 	free(url);
@@ -343,7 +346,8 @@ void css_atimport_callback(content_msg msg, struct content *css,
 			c->data.css.import_content[i] = fetchcache(
 					c->data.css.import_url[i], c->url, css_atimport_callback,
 					c, i, css->width, css->height);
-			if (c->data.css.import_content[i]->status != CONTENT_STATUS_DONE)
+			if (c->data.css.import_content[i] &&
+					c->data.css.import_content[i]->status != CONTENT_STATUS_DONE)
 				c->active++;
 			break;
 
diff --git a/debug/netsurfd.c b/debug/netsurfd.c
index c5ad28e9d..f73e44954 100644
--- a/debug/netsurfd.c
+++ b/debug/netsurfd.c
@@ -40,10 +40,14 @@ int main(int argc, char *argv[])
 		puts("=== URL:");
 		gets(url);
 		c = fetchcache(url, 0, callback, 0, 0, 100, 1000);
-		done = c->status == CONTENT_STATUS_DONE;
-		while (!done)
-			fetch_poll();
-		puts("=== SUCCESS, dumping cache");
+		if (c) {
+			done = c->status == CONTENT_STATUS_DONE;
+			while (!done)
+				fetch_poll();
+			puts("=== SUCCESS, dumping cache");
+		} else {
+			puts("=== FAILURE, dumping cache");
+		}
 		cache_dump();
 		content_remove_user(c, callback, 0, 0);
 	}
diff --git a/desktop/browser.c b/desktop/browser.c
index 4f9fcc362..ad29e6f38 100644
--- a/desktop/browser.c
+++ b/desktop/browser.c
@@ -230,6 +230,10 @@ void browser_window_open_location_historical(struct browser_window* bw, const ch
   bw->time0 = clock();
   bw->loading_content = fetchcache(url, 0, browser_window_callback, bw, 0,
 		  gui_window_get_width(bw->window), 0);
+  if (bw->loading_content == 0) {
+    browser_window_set_status(bw, "Unable to fetch document");
+    return;
+  }
   if (bw->loading_content->status == CONTENT_STATUS_READY)
     browser_window_callback(CONTENT_MSG_READY, bw->loading_content, bw, 0, 0);
   else if (bw->loading_content->status == CONTENT_STATUS_DONE)
diff --git a/render/html.c b/render/html.c
index 440b8fd0c..be0044fce 100644
--- a/render/html.c
+++ b/render/html.c
@@ -176,7 +176,8 @@ void html_convert_css_callback(content_msg msg, struct content *css,
 			c->data.html.stylesheet_content[i] = fetchcache(
 					error, c->url, html_convert_css_callback,
 					c, i, css->width, css->height);
-			if (c->data.html.stylesheet_content[i]->status != CONTENT_STATUS_DONE)
+			if (c->data.html.stylesheet_content[i] != 0 &&
+					c->data.html.stylesheet_content[i]->status != CONTENT_STATUS_DONE)
 				c->active++;
 			break;
 
@@ -228,6 +229,7 @@ void html_find_stylesheets(struct content *c, xmlNode *head)
 			c->url,
 			html_convert_css_callback,
 			c, 0, c->width, c->height);
+	assert(c->data.html.stylesheet_content[0] != 0);
 	if (c->data.html.stylesheet_content[0]->status != CONTENT_STATUS_DONE)
 		c->active++;
 
@@ -278,7 +280,8 @@ void html_find_stylesheets(struct content *c, xmlNode *head)
 			c->data.html.stylesheet_content[i] = fetchcache(url, c->url,
 					html_convert_css_callback, c, i,
 					c->width, c->height);
-			if (c->data.html.stylesheet_content[i]->status != CONTENT_STATUS_DONE)
+			if (c->data.html.stylesheet_content[i] &&
+					c->data.html.stylesheet_content[i]->status != CONTENT_STATUS_DONE)
 				c->active++;
 			free(url);
 			i++;
@@ -362,10 +365,12 @@ void html_fetch_object(struct content *c, char *url, struct box *box)
 			c->width, c->height);  /* we don't know the object's
 						  dimensions yet; use
 						  parent's as an estimate */
-	c->active++;
-	if (c->data.html.object[i].content->status == CONTENT_STATUS_DONE)
-		html_object_callback(CONTENT_MSG_DONE,
-				c->data.html.object[i].content, c, i, 0);
+	if (c->data.html.object[i].content) {
+		c->active++;
+		if (c->data.html.object[i].content->status == CONTENT_STATUS_DONE)
+			html_object_callback(CONTENT_MSG_DONE,
+					c->data.html.object[i].content, c, i, 0);
+	}
 	c->data.html.object_count++;
 }
 
@@ -453,7 +458,8 @@ void html_object_callback(content_msg msg, struct content *object,
 			c->data.html.object[i].content = fetchcache(
 					error, c->url, html_object_callback,
 					c, i, 0, 0);
-			if (c->data.html.object[i].content->status != CONTENT_STATUS_DONE)
+			if (c->data.html.object[i].content &&
+					c->data.html.object[i].content->status != CONTENT_STATUS_DONE)
 				c->active++;
 			break;
 
@@ -519,7 +525,8 @@ void html_revive(struct content *c, unsigned int width, unsigned int height)
 					c->data.html.object[i].url, c->url,
 					html_object_callback,
 					c, i, 0, 0);
-			if (c->data.html.object[i].content->status != CONTENT_STATUS_DONE)
+			if (c->data.html.object[i].content &&
+					c->data.html.object[i].content->status != CONTENT_STATUS_DONE)
 				c->active++;
 		}
 	}