diff --git a/kallithea/model/scm.py b/kallithea/model/scm.py
--- a/kallithea/model/scm.py
+++ b/kallithea/model/scm.py
@@ -704,6 +704,10 @@ class ScmModel(object):
                 log.warning('skipping overwriting hook file %s', hook_file)
             else:
                 log.debug('writing hook file %s', hook_file)
+                if other_hook:
+                    backup_file = hook_file + '.bak'
+                    log.warning('moving existing hook to %s', backup_file)
+                    os.rename(hook_file, backup_file)
                 try:
                     fh, fn = tempfile.mkstemp(prefix=hook_file + '.tmp.')
                     os.write(fh, tmpl.replace(b'_TMPL_', safe_bytes(kallithea.__version__)))
diff --git a/kallithea/templates/admin/settings/settings_mapping.html b/kallithea/templates/admin/settings/settings_mapping.html
--- a/kallithea/templates/admin/settings/settings_mapping.html
+++ b/kallithea/templates/admin/settings/settings_mapping.html
@@ -25,14 +25,14 @@ ${h.form(url('admin_settings_mapping'), 
                             ${_('Install Git hooks')}
                         </label>
                     </div>
-                    <span class="help-block">${_("Verify if Kallithea's Git hooks are installed for each repository. Current hooks will be updated to the latest version.")}</span>
+                    <span class="help-block">${_("Install Kallithea's internal hooks for all Git repositories where they are missing or can be upgraded. Existing hooks that don't seem to come from Kallithea will not be touched.")}</span>
                     <div class="checkbox">
                         <label>
                             ${h.checkbox('hooks_overwrite', True)}
-                            ${_('Overwrite existing Git hooks')}
+                            ${_('Install and overwrite Git hooks')}
                         </label>
                     </div>
-                    <span class="help-block">${_("If installing Git hooks, overwrite any existing hooks, even if they do not seem to come from Kallithea. WARNING: This operation will destroy any custom git hooks you may have deployed by hand!")}</span>
+                    <span class="help-block">${_("Install Kallithea's internal hooks for all Git repositories. Existing hooks that don't seem to come from Kallithea will be disabled by renaming to .bak extension.")}</span>
                 </div>
             </div>