diff -r 868db5c1f2d7 -r 5cbb66c24fc6 update/update.c
--- a/update/update.c	Thu Aug 13 19:01:16 2009 +0100
+++ b/update/update.c	Fri Mar 23 20:29:50 2012 +0000
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2009  J. Ali Harlow <ali@juiblex.co.uk>
+ * Copyright (C) 2009, 2011  J. Ali Harlow <ali@juiblex.co.uk>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -17,6 +17,7 @@
  */
 
 #include <stdlib.h>
+#include <stdio.h>
 #include <lua.h>
 #include "config.h"
 #include "plover/plover.h"
@@ -27,6 +28,7 @@
 void update(const char *argv0)
 {
     char *path,*s,*prefix;
+    int ch;
     struct comps *comps;
     path=plover_get_program_directory(argv0);
     s=plover_strconcat(path,"/repodata/comps.xml",NULL);
@@ -38,6 +40,18 @@
     }
     free(s);
     prefix=plover_default_prefix_for_vendor(comps->vendor);
+    if (!plover_installed_files_match_prefix(prefix))
+    {
+	printf("The existing installation is not under %s\n"
+	  "In order to continue, all the existing packages must be removed.\n"
+	  "Do you want to remove all existing packages? ",prefix);
+	ch=getchar();
+	if (ch!='y' && ch!='Y' && ch!=EOF && ch!='\n')
+	    exit(1);
+	while(ch!='\n' && ch!=EOF)
+	    ch=getchar();
+	plover_remove(NULL);
+    }
     plover_comps_free(comps);
     plover_update(path,prefix,NULL);
     free(prefix);
@@ -49,4 +63,5 @@
     razor_set_lua_loader("posix",luaopen_posix);
     razor_set_lua_loader("whelk",luaopen_whelk);
     update(argv[0]);
+    exit(0);
 }