diff --git a/mailnews/imap/src/nsImapIncomingServer.cpp b/mailnews/imap/src/nsImapIncomingServer.cpp
index ad6c4afdf787..dc24b1fff0ac 100644
--- a/mailnews/imap/src/nsImapIncomingServer.cpp
+++ b/mailnews/imap/src/nsImapIncomingServer.cpp
@@ -891,6 +891,7 @@ nsImapIncomingServer::CloseCachedConnections()
 // nsIImapServerSink impl
 NS_IMETHODIMP nsImapIncomingServer::PossibleImapMailbox(const char *folderPath, PRUnichar hierarchyDelimiter, PRInt32 boxFlags)
 {
+  // folderPath is in canonical format, i.e., hierarchy separator has been replaced with '/'
 	nsresult rv;
     PRBool found = PR_FALSE;
 	PRBool haveParent = PR_FALSE;
@@ -923,7 +924,7 @@ NS_IMETHODIMP nsImapIncomingServer::PossibleImapMailbox(const char *folderPath,
 
     uri.Assign(serverUri);
 
-    PRInt32 leafPos = folderName.RFindChar(hierarchyDelimiter);
+    PRInt32 leafPos = folderName.RFindChar('/');
 
     nsCAutoString parentName(folderName);
 	nsCAutoString parentUri(uri);
@@ -1014,7 +1015,10 @@ NS_IMETHODIMP nsImapIncomingServer::PossibleImapMailbox(const char *folderPath,
       imapFolder->SetBoxFlags(boxFlags);
       imapFolder->SetExplicitlyVerify(explicitlyVerify);
       imapFolder->GetOnlineName(getter_Copies(onlineName));
-			if (! ((const char*) onlineName) || nsCRT::strlen((const char *) onlineName) == 0
+      // online name needs to use the correct hierarchy delimiter (I think...)
+      // or the canonical path - one or the other, but be consistent.
+      dupFolderPath.ReplaceChar('/', hierarchyDelimiter);
+      if (! ((const char*) onlineName) || nsCRT::strlen((const char *) onlineName) == 0
 				|| nsCRT::strcmp((const char *) onlineName, dupFolderPath))
 				imapFolder->SetOnlineName(dupFolderPath);
 			if (NS_SUCCEEDED(CreatePRUnicharStringFromUTF7(folderName, getter_Copies(unicodeName))))
diff --git a/mailnews/imap/src/nsImapMailFolder.cpp b/mailnews/imap/src/nsImapMailFolder.cpp
index 79d9b8cd81d2..e77101ef6ce9 100644
--- a/mailnews/imap/src/nsImapMailFolder.cpp
+++ b/mailnews/imap/src/nsImapMailFolder.cpp
@@ -570,7 +570,7 @@ NS_IMETHODIMP nsImapMailFolder::CreateClientSubfolderInfo(const char *folderName
     nsAutoString leafName; leafName.AssignWithConversion(folderName);
     nsAutoString folderNameStr;
     nsAutoString parentName = leafName;
-    PRInt32 folderStart = leafName.FindChar(hierarchyDelimiter);
+    PRInt32 folderStart = leafName.FindChar('/');
     if (folderStart > 0)
     {
         NS_WITH_SERVICE(nsIRDFService, rdf, kRDFServiceCID, &rv);