diff --git a/kallithea/controllers/pullrequests.py b/kallithea/controllers/pullrequests.py
--- a/kallithea/controllers/pullrequests.py
+++ b/kallithea/controllers/pullrequests.py
@@ -576,6 +576,8 @@ class PullrequestsController(BaseRepoCon
                            for x in c.pull_request.revisions]
         except ChangesetDoesNotExistError:
             c.cs_ranges = []
+            h.flash(_('Revision %s not found in %s') % (x, c.cs_repo.repo_name),
+                'error')
         c.cs_ranges_org = None # not stored and not important and moving target - could be calculated ...
         revs = [ctx.revision for ctx in reversed(c.cs_ranges)]
         c.jsdata = json.dumps(graph_data(org_scm_instance, revs))
@@ -600,7 +602,9 @@ class PullrequestsController(BaseRepoCon
         c.update_msg = ""
         c.update_msg_other = ""
         try:
-            if org_scm_instance.alias == 'hg' and c.a_ref_name != 'ancestor':
+            if not c.cs_ranges:
+                c.update_msg = _('Error: changesets not found when displaying pull request from %s.') % c.cs_rev
+            elif org_scm_instance.alias == 'hg' and c.a_ref_name != 'ancestor':
                 if c.cs_ref_type != 'branch':
                     c.cs_branch_name = org_scm_instance.get_changeset(c.cs_ref_name).branch # use ref_type ?
                 c.a_branch_name = c.a_ref_name
@@ -654,7 +658,7 @@ class PullrequestsController(BaseRepoCon
                 c.cs_repo.scm_instance.get_changeset(c.cs_rev) # check it exists - raise ChangesetDoesNotExistError if not
                 c.update_msg = _("Git pull requests don't support iterating yet.")
         except ChangesetDoesNotExistError:
-            c.update_msg = _('Error: revision %s was not found. Please create a new pull request!') % c.cs_rev
+            c.update_msg = _('Error: some changesets not found when displaying pull request from %s.') % c.cs_rev
 
         c.avail_revs = avail_revs
         c.avail_cs = [org_scm_instance.get_changeset(r) for r in avail_show]
diff --git a/kallithea/templates/pullrequests/pullrequest_show.html b/kallithea/templates/pullrequests/pullrequest_show.html
--- a/kallithea/templates/pullrequests/pullrequest_show.html
+++ b/kallithea/templates/pullrequests/pullrequest_show.html
@@ -133,6 +133,7 @@ ${self.repo_context_bar('showpullrequest
               <label>${_('Pull changes')}:</label>
           </div>
           <div class="input">
+            %if c.cs_ranges:
               <div>
                ## TODO: use cs_ranges[-1] or org_ref_parts[1] in both cases?
                %if h.is_hg(c.pull_request.org_repo):
@@ -141,6 +142,7 @@ ${self.repo_context_bar('showpullrequest
                  <span style="font-family: monospace">git pull ${c.pull_request.org_repo.clone_url()} ${c.pull_request.org_ref_parts[1]}</span>
                %endif
               </div>
+            %endif
           </div>
         </div>
         <div class="field">
@@ -180,7 +182,7 @@ ${self.repo_context_bar('showpullrequest
                 <table id="updaterevs-table" class="noborder" style="padding-left:50px">
                   %for cnt, cs in enumerate(c.avail_cs):
                     <tr id="chg_available_${cnt+1}">
-                      %if cs.revision == c.cs_ranges[-1].revision:
+                      %if c.cs_ranges and cs.revision == c.cs_ranges[-1].revision:
                         <td>
                           %if editable:
                             ${h.radio(name='updaterev', value='', checked=True)}