diff --git a/client/cs_account.cpp b/client/cs_account.cpp
index 38a29eae67..53c5032924 100644
--- a/client/cs_account.cpp
+++ b/client/cs_account.cpp
@@ -323,6 +323,7 @@ int CLIENT_STATE::parse_account_files() {
     PROJECT* project;
     FILE* f;
     int retval;
+    char path[MAXPATHLEN];
 
     DirScanner dir(".");
     while (dir.scan(name)) {
@@ -345,16 +346,50 @@ int CLIENT_STATE::parse_account_files() {
                 "Couldn't parse account file %s", name.c_str()
             );
             delete project;
-        } else {
-            if (lookup_project(project->master_url)) {
+            continue;
+        }
+
+        // see if the account file name doesn't match the master URL.
+        // This can happen if a project changes its URL
+        //
+        // If this happens, anything in client_state.xml for the old project
+        // will be ignored.
+        //
+        get_account_filename(project->master_url, path, sizeof(path));
+        if (strcmp(path, name.c_str())) {
+            // if not, see if account file with proper name exists
+            //
+            if (boinc_file_exists(path)) {
+                // yes - delete this file
+                //
                 msg_printf(project, MSG_INFO,
-                    "Duplicate account file %s - ignoring", name.c_str()
+                    "Misnamed account file %s - deleting", name.c_str()
                 );
+                boinc_delete_file(name.c_str());
                 delete project;
+                continue;
             } else {
-                projects.push_back(project);
+                // no - rename this file
+                //
+                msg_printf(project, MSG_INFO,
+                    "Misnamed account file %s - renaming to %s",
+                    name.c_str(), path
+                );
+                boinc_rename(name.c_str(), path);
             }
         }
+
+        // shouldn't happen given the above logic, but just in case
+        //
+        if (lookup_project(project->master_url)) {
+            msg_printf(project, MSG_INFO,
+                "Duplicate account file %s - ignoring", name.c_str()
+            );
+            delete project;
+            continue;
+        }
+
+        projects.push_back(project);
     }
     return 0;
 }
diff --git a/client/cs_files.cpp b/client/cs_files.cpp
index 6c020425a6..e3330ba43a 100644
--- a/client/cs_files.cpp
+++ b/client/cs_files.cpp
@@ -87,15 +87,39 @@ bool CLIENT_STATE::start_new_file_xfer(PERS_FILE_XFER& pfx) {
     return true;
 }
 
-// Make a directory for each of the projects in the client state
+// Make a directory for each of the projects in the client state,
+// and delete other stuff in projects/
 //
 int CLIENT_STATE::make_project_dirs() {
     unsigned int i;
     int retval;
+    vector<string> pds;
     for (i=0; i<projects.size(); i++) {
-        retval = make_project_dir(*projects[i]);
+        PROJECT *p = projects[i];
+        retval = make_project_dir(*p);
         if (retval) return retval;
+        pds.push_back(p->project_dir());
     }
+
+    string name;
+    char path[MAXPATHLEN];
+    DirScanner dir("projects");
+    while (dir.scan(name)) {
+        snprintf(path, sizeof(path), "projects/%s", name.c_str());
+        if (std::find(pds.begin(), pds.end(), path) != pds.end()) {
+            continue;
+        }
+        msg_printf(0, MSG_INFO,
+            "%s is not a project dir - removing", path
+        );
+        if (is_dir(path)) {
+            clean_out_dir(path);
+            boinc_rmdir(path);
+        } else {
+            boinc_delete_file(path);
+        }
+    }
+
     return 0;
 }
 
diff --git a/client/cs_scheduler.cpp b/client/cs_scheduler.cpp
index 2242948945..42a923761f 100644
--- a/client/cs_scheduler.cpp
+++ b/client/cs_scheduler.cpp
@@ -567,7 +567,9 @@ int CLIENT_STATE::handle_scheduler_reply(
     // (which comes from the project's config.xml).
     // - if http -> https transition, use the https: one from now on
     // - if https -> http transition, keep using the https: one
-    // - otherwise notify the user.
+    // - otherwise switch to the new master URL:
+    //      rename and rewrite account file
+    //      rename project dir
     //
     if (strlen(sr.master_url)) {
         canonicalize_master_url(sr.master_url, sizeof(sr.master_url));
@@ -587,9 +589,41 @@ int CLIENT_STATE::handle_scheduler_reply(
                 // keep using https://
             } else {
                 msg_printf(project, MSG_USER_ALERT,
-                    _("This project seems to have changed its URL.  When convenient, remove the project, then add %s"),
-                    sr.master_url
+                    _("Master URL changed from %s to %s"),
+                    current_url.c_str(), reply_url.c_str()
                 );
+                char path[MAXPATHLEN], path2[MAXPATHLEN], old_project_dir[MAXPATHLEN];
+
+                // rename statistics file
+                //
+                get_statistics_filename(
+                    (char*)current_url.c_str(), path, sizeof(path)
+                );
+                get_statistics_filename(
+                    (char*)reply_url.c_str(), path2, sizeof(path2)
+                );
+                boinc_rename(path, path2);
+
+                strcpy(old_project_dir, project->project_dir());
+
+                // delete account file and write new one
+                //
+                get_account_filename(project->master_url, path, sizeof(path));
+                boinc_delete_file(path);
+                strcpy(project->master_url, reply_url.c_str());
+                project->write_account_file();
+
+                // rename project dir
+                //
+                strcpy(project->_project_dir, "");
+                strcpy(path2, project->project_dir());
+                boinc_rename(old_project_dir, path2);
+
+                // reset the project (clear jobs etc.).
+                // If any jobs are running, their soft links
+                // point to the old project dir
+                //
+                reset_project(project, false);
             }
         }
     }