diff -r 8585fdace215 MoinMoin/script/maint/cleancache.py
--- a/MoinMoin/script/maint/cleancache.py	Fri Dec 19 23:35:57 2008 +0100
+++ b/MoinMoin/script/maint/cleancache.py	Wed Dec 24 08:48:15 2008 +0100
@@ -6,6 +6,7 @@
             2007-2008 MoinMoin:ReimarBauer
 @license: GNU GPL, see COPYING for details.
 """
+import urllib
 
 from MoinMoin import caching
 from MoinMoin.Page import Page
@@ -41,7 +42,16 @@
     def mainloop(self):
         self.init_request()
         request = self.request
+        site = None
+        try:
+            site = urllib.urlopen(self.options.wiki_url)
+        except:
+            pass
 
+        if site:
+            print "***************************************************"
+            print "Please STOP your wiki and retry to clean your cache."
+            return
         # clean page scope cache entries
         keys = ['text_html', 'pagelinks', 'hitcounts', ]
         pages = request.rootpage.getPageList(user='')
diff -r 8585fdace215 MoinMoin/script/migration/data.py
--- a/MoinMoin/script/migration/data.py	Fri Dec 19 23:35:57 2008 +0100
+++ b/MoinMoin/script/migration/data.py	Wed Dec 24 08:48:15 2008 +0100
@@ -17,7 +17,7 @@
     @license: GNU GPL, see COPYING for details.
 """
 
-import os
+import os, urllib
 
 from MoinMoin import wikiutil
 from MoinMoin.script import MoinScript
@@ -37,6 +37,17 @@
         request = self.request
         data_dir = request.cfg.data_dir
         meta_fname = os.path.join(data_dir, 'meta')
+        site = None
+        try:
+            site = urllib.urlopen(self.options.wiki_url)
+        except:
+            pass
+
+        if site:
+            print "****************************************************"
+            print "Please STOP your wiki and retry to migrate your data."
+            return
+        
         while True:
             try:
                 meta = wikiutil.MetaDict(meta_fname, request.cfg.cache_dir)
@@ -58,4 +69,5 @@
                     break
             finally:
                 del meta
-
+                print "*****************************************************************************"
+                print "You may want to continue with cleaning your cache files, see maint cleancache."