Index: class-wp-upgrader.php
===================================================================
--- class-wp-upgrader.php	(revision 25761)
+++ class-wp-upgrader.php	(working copy)
@@ -213,7 +213,7 @@
 		if ( 1 == count($source_files) && $wp_filesystem->is_dir( trailingslashit($source) . $source_files[0] . '/') ) //Only one folder? Then we want its contents.
 			$source = trailingslashit($source) . trailingslashit($source_files[0]);
 		elseif ( count($source_files) == 0 )
-			return new WP_Error( 'incompatible_archive', $this->strings['incompatible_archive'], $this->strings['no_files'] ); //There are no files?
+			return new WP_Error( 'incompatible_archive_empty', $this->strings['incompatible_archive'], $this->strings['no_files'] ); //There are no files?
 		else //It's only a single file, the upgrader will use the foldername of this file as the destination folder. foldername is based on zip filename.
 			$source = trailingslashit($source);
 
@@ -262,7 +262,7 @@
 		//Create destination if needed
 		if ( !$wp_filesystem->exists($remote_destination) )
 			if ( !$wp_filesystem->mkdir($remote_destination, FS_CHMOD_DIR) )
-				return new WP_Error('mkdir_failed', $this->strings['mkdir_failed'], $remote_destination);
+				return new WP_Error('mkdir_failed_destination', $this->strings['mkdir_failed'], $remote_destination);
 
 		// Copy new version of item into place.
 		$result = copy_dir($source, $remote_destination);
@@ -623,7 +623,7 @@
 		}
 
 		if ( ! $plugins_found )
-			return new WP_Error( 'incompatible_archive', $this->strings['incompatible_archive'], __('No valid plugins were found.') );
+			return new WP_Error( 'incompatible_archive_no_plugins', $this->strings['incompatible_archive'], __('No valid plugins were found.') );
 
 		return $source;
 	}
@@ -989,16 +989,16 @@
 
 		// A proper archive should have a style.css file in the single subdirectory
 		if ( ! file_exists( $working_directory . 'style.css' ) )
-			return new WP_Error( 'incompatible_archive', $this->strings['incompatible_archive'], __('The theme is missing the <code>style.css</code> stylesheet.') );
+			return new WP_Error( 'incompatible_archive_theme_no_style', $this->strings['incompatible_archive'], __('The theme is missing the <code>style.css</code> stylesheet.') );
 
 		$info = get_file_data( $working_directory . 'style.css', array( 'Name' => 'Theme Name', 'Template' => 'Template' ) );
 
 		if ( empty( $info['Name'] ) )
-			return new WP_Error( 'incompatible_archive', $this->strings['incompatible_archive'], __("The <code>style.css</code> stylesheet doesn't contain a valid theme header.") );
+			return new WP_Error( 'incompatible_archive_theme_no_name', $this->strings['incompatible_archive'], __("The <code>style.css</code> stylesheet doesn't contain a valid theme header.") );
 
 		// If it's not a child theme, it must have at least an index.php to be legit.
 		if ( empty( $info['Template'] ) && ! file_exists( $working_directory . 'index.php' ) )
-			return new WP_Error( 'incompatible_archive', $this->strings['incompatible_archive'], __('The theme is missing the <code>index.php</code> file.') );
+			return new WP_Error( 'incompatible_archive_theme_no_index', $this->strings['incompatible_archive'], __('The theme is missing the <code>index.php</code> file.') );
 
 		return $source;
 	}
@@ -1141,7 +1141,7 @@
 		$remote_destination = $wp_filesystem->find_folder( WP_LANG_DIR );
 		if ( ! $wp_filesystem->exists( $remote_destination ) )
 			if ( ! $wp_filesystem->mkdir( $remote_destination, FS_CHMOD_DIR ) )
-				return new WP_Error( 'mkdir_failed', $this->strings['mkdir_failed'], $remote_destination );
+				return new WP_Error( 'mkdir_failed_lang_dir', $this->strings['mkdir_failed'], $remote_destination );
 
 		foreach ( $language_updates as $language_update ) {
 
@@ -1200,7 +1200,7 @@
 		}
 
 		if ( ! $mo || ! $po )
-			return new WP_Error( 'incompatible_archive', $this->strings['incompatible_archive'],
+			return new WP_Error( 'incompatible_archive_pomo', $this->strings['incompatible_archive'],
 				__( 'The language pack is missing either the <code>.po</code> or <code>.mo</code> files.' ) );
 
 		return $source;
@@ -1287,7 +1287,7 @@
 		// Copy update-core.php from the new version into place.
 		if ( !$wp_filesystem->copy($working_dir . '/wordpress/wp-admin/includes/update-core.php', $wp_dir . 'wp-admin/includes/update-core.php', true) ) {
 			$wp_filesystem->delete($working_dir, true);
-			return new WP_Error('copy_failed', $this->strings['copy_failed']);
+			return new WP_Error('copy_failed_for_update_core_file', $this->strings['copy_failed']);
 		}
 		$wp_filesystem->chmod($wp_dir . 'wp-admin/includes/update-core.php', FS_CHMOD_FILE);
 
Index: file.php
===================================================================
--- file.php	(revision 25761)
+++ file.php	(working copy)
@@ -603,7 +603,7 @@
 
 	for ( $i = 0; $i < $z->numFiles; $i++ ) {
 		if ( ! $info = $z->statIndex($i) )
-			return new WP_Error('stat_failed', __('Could not retrieve file from archive.'));
+			return new WP_Error('stat_failed_ziparchive', __('Could not retrieve file from archive.'));
 
 		if ( '__MACOSX/' === substr($info['name'], 0, 9) ) // Skip the OS X-created __MACOSX directory
 			continue;
@@ -633,13 +633,13 @@
 	// Create those directories if need be:
 	foreach ( $needed_dirs as $_dir ) {
 		if ( ! $wp_filesystem->mkdir($_dir, FS_CHMOD_DIR) && ! $wp_filesystem->is_dir($_dir) ) // Only check to see if the Dir exists upon creation failure. Less I/O this way.
-			return new WP_Error('mkdir_failed', __('Could not create directory.'), $_dir);
+			return new WP_Error('mkdir_failed_ziparchive', __('Could not create directory.'), $_dir);
 	}
 	unset($needed_dirs);
 
 	for ( $i = 0; $i < $z->numFiles; $i++ ) {
 		if ( ! $info = $z->statIndex($i) )
-			return new WP_Error('stat_failed', __('Could not retrieve file from archive.'));
+			return new WP_Error('stat_failed_ziparchive', __('Could not retrieve file from archive.'));
 
 		if ( '/' == substr($info['name'], -1) ) // directory
 			continue;
@@ -649,10 +649,10 @@
 
 		$contents = $z->getFromIndex($i);
 		if ( false === $contents )
-			return new WP_Error('extract_failed', __('Could not extract file from archive.'), $info['name']);
+			return new WP_Error('extract_failed_ziparchive', __('Could not extract file from archive.'), $info['name']);
 
 		if ( ! $wp_filesystem->put_contents( $to . $info['name'], $contents, FS_CHMOD_FILE) )
-			return new WP_Error('copy_failed', __('Could not copy file.'), $to . $info['name']);
+			return new WP_Error('copy_failed_ziparchive', __('Could not copy file.'), $to . $info['name']);
 	}
 
 	$z->close();
@@ -691,7 +691,7 @@
 		return new WP_Error('incompatible_archive', __('Incompatible Archive.'), $archive->errorInfo(true));
 
 	if ( 0 == count($archive_files) )
-		return new WP_Error('empty_archive', __('Empty archive.'));
+		return new WP_Error('empty_archive_pclzip', __('Empty archive.'));
 
 	// Determine any children directories needed (From within the archive)
 	foreach ( $archive_files as $file ) {
@@ -720,7 +720,7 @@
 	// Create those directories if need be:
 	foreach ( $needed_dirs as $_dir ) {
 		if ( ! $wp_filesystem->mkdir($_dir, FS_CHMOD_DIR) && ! $wp_filesystem->is_dir($_dir) ) // Only check to see if the dir exists upon creation failure. Less I/O this way.
-			return new WP_Error('mkdir_failed', __('Could not create directory.'), $_dir);
+			return new WP_Error('mkdir_failed_pclzip', __('Could not create directory.'), $_dir);
 	}
 	unset($needed_dirs);
 
@@ -733,7 +733,7 @@
 			continue;
 
 		if ( ! $wp_filesystem->put_contents( $to . $file['filename'], $file['content'], FS_CHMOD_FILE) )
-			return new WP_Error('copy_failed', __('Could not copy file.'), $to . $file['filename']);
+			return new WP_Error('copy_failed_pclzip', __('Could not copy file.'), $to . $file['filename']);
 	}
 	return true;
 }
@@ -766,12 +766,12 @@
 				// If copy failed, chmod file to 0644 and try again.
 				$wp_filesystem->chmod($to . $filename, 0644);
 				if ( ! $wp_filesystem->copy($from . $filename, $to . $filename, true, FS_CHMOD_FILE) )
-					return new WP_Error('copy_failed', __('Could not copy file.'), $to . $filename);
+					return new WP_Error('copy_failed_copy_dir', __('Could not copy file.'), $to . $filename);
 			}
 		} elseif ( 'd' == $fileinfo['type'] ) {
 			if ( !$wp_filesystem->is_dir($to . $filename) ) {
 				if ( !$wp_filesystem->mkdir($to . $filename, FS_CHMOD_DIR) )
-					return new WP_Error('mkdir_failed', __('Could not create directory.'), $to . $filename);
+					return new WP_Error('mkdir_failed_copy_dir', __('Could not create directory.'), $to . $filename);
 			}
 
 			// generate the $sub_skip_list for the subdirectory as a sub-set of the existing $skip_list
Index: update-core.php
===================================================================
--- update-core.php	(revision 25761)
+++ update-core.php	(working copy)
@@ -661,7 +661,7 @@
 	$versions_file = trailingslashit( $wp_filesystem->wp_content_dir() ) . 'upgrade/version-current.php';
 	if ( ! $wp_filesystem->copy( $from . $distro . 'wp-includes/version.php', $versions_file ) ) {
 		 $wp_filesystem->delete( $from, true );
-		 return new WP_Error( 'copy_failed', __('Could not copy file.') );
+		 return new WP_Error( 'copy_failed_for_version_file', __('Could not copy file.') );
 	}
 
 	$wp_filesystem->chmod( $versions_file, FS_CHMOD_FILE );
@@ -741,10 +741,13 @@
 			$total_size += filesize( $working_dir_local . '/' . $file ); 
 
 		// If we don't have enough free space, it isn't worth trying again
-		if ( $total_size >= disk_free_space( ABSPATH ) )
+		if ( $total_size >= disk_free_space( ABSPATH ) ) {
 			$result = new WP_Error( 'disk_full', __( 'There is not enough free disk space to complete the update.' ), $to );
-		else
+		} else {
 			$result = _copy_dir( $from . $distro, $to, $skip );
+			if ( is_wp_error( $result ) )
+				$result = new WP_Error( $result->get_error_code() . '_retry', $result->get_error_message(), $result->get_error_data() );
+		}
 	}
 
 	// Custom Content Directory needs updating now.
@@ -800,7 +803,7 @@
 						continue;
 
 					if ( ! $wp_filesystem->copy($from . $distro . 'wp-content/' . $file, $dest . $filename, FS_CHMOD_FILE) )
-						$result = new WP_Error('copy_failed', __('Could not copy file.'), $dest . $filename);
+						$result = new WP_Error('copy_failed_for_new_bundled', __('Could not copy file.'), $dest . $filename);
 				} else {
 					if ( ! $development_build && $wp_filesystem->is_dir( $dest . $filename ) )
 						continue;
@@ -887,12 +890,12 @@
 				// If copy failed, chmod file to 0644 and try again.
 				$wp_filesystem->chmod($to . $filename, 0644);
 				if ( ! $wp_filesystem->copy($from . $filename, $to . $filename, true, FS_CHMOD_FILE) )
-					return new WP_Error('copy_failed', __('Could not copy file.'), $to . $filename);
+					return new WP_Error('copy_failed__copy_dir', __('Could not copy file.'), $to . $filename);
 			}
 		} elseif ( 'd' == $fileinfo['type'] ) {
 			if ( !$wp_filesystem->is_dir($to . $filename) ) {
 				if ( !$wp_filesystem->mkdir($to . $filename, FS_CHMOD_DIR) )
-					return new WP_Error('mkdir_failed', __('Could not create directory.'), $to . $filename);
+					return new WP_Error('mkdir_failed__copy_dir', __('Could not create directory.'), $to . $filename);
 			}
 
 			// generate the $sub_skip_list for the subdirectory as a sub-set of the existing $skip_list