--- a/services/sync/modules/policies.js
+++ b/services/sync/modules/policies.js
@@ -515,34 +515,36 @@ let ErrorHandler = {
         let engine_name = data;   // engine name that threw the exception
 
         this.checkServerError(exception);
 
         Status.engines = [engine_name, exception.failureCode || ENGINE_UNKNOWN_FAIL];
         this._log.debug(engine_name + " failed: " + Utils.exceptionStr(exception));
         break;
       case "weave:service:login:error":
+        this.resetFileLog(Svc.Prefs.get("log.appender.file.logOnError"),
+                          LOG_PREFIX_ERROR);
+
         if (this.shouldReportError()) {
-          this.resetFileLog(Svc.Prefs.get("log.appender.file.logOnError"),
-                            LOG_PREFIX_ERROR);
           this.notifyOnNextTick("weave:ui:login:error");
         } else {
           this.notifyOnNextTick("weave:ui:clear-error");
         }
 
         this.dontIgnoreErrors = false;
         break;
       case "weave:service:sync:error":
         if (Status.sync == CREDENTIALS_CHANGED) {
           Weave.Service.logout();
         }
 
+        this.resetFileLog(Svc.Prefs.get("log.appender.file.logOnError"),
+                          LOG_PREFIX_ERROR);
+
         if (this.shouldReportError()) {
-          this.resetFileLog(Svc.Prefs.get("log.appender.file.logOnError"),
-                            LOG_PREFIX_ERROR);
           this.notifyOnNextTick("weave:ui:sync:error");
         } else {
           this.notifyOnNextTick("weave:ui:sync:finish");
         }
 
         this.dontIgnoreErrors = false;
         break;
       case "weave:service:sync:finish":

--- a/services/sync/tests/unit/test_errorhandler.js
+++ b/services/sync/tests/unit/test_errorhandler.js
@@ -1259,16 +1259,72 @@ add_test(function test_sync_engine_gener
     server.stop(run_next_test);
   });
 
   do_check_eq(Status.engines["catapult"], undefined);
   do_check_true(setUp());
   Service.sync();
 });
 
+add_test(function test_logs_on_sync_error_despite_shouldReportError() {
+  _("Ensure that an error is still logged when weave:service:sync:error " +
+    "is notified, despite shouldReportError returning false.");
+
+  let log = Log4Moz.repository.getLogger("Sync.ErrorHandler");
+  Svc.Prefs.set("log.appender.file.logOnError", true);
+  log.info("TESTING");
+
+  // Ensure that we report no error.
+  Status.login = MASTER_PASSWORD_LOCKED;
+  do_check_false(ErrorHandler.shouldReportError());
+
+  Svc.Obs.add("weave:service:reset-file-log", function onResetFileLog() {
+    Svc.Obs.remove("weave:service:reset-file-log", onResetFileLog);
+
+    // Test that error log was written.
+    let entries = logsdir.directoryEntries;
+    do_check_true(entries.hasMoreElements());
+    let logfile = entries.getNext().QueryInterface(Ci.nsILocalFile);
+    do_check_eq(logfile.leafName.slice(0, LOG_PREFIX_ERROR.length),
+                LOG_PREFIX_ERROR);
+
+    clean();
+    run_next_test();
+  });
+  Svc.Obs.notify("weave:service:sync:error", {});
+});
+
+add_test(function test_logs_on_login_error_despite_shouldReportError() {
+  _("Ensure that an error is still logged when weave:service:login:error " +
+    "is notified, despite shouldReportError returning false.");
+
+  let log = Log4Moz.repository.getLogger("Sync.ErrorHandler");
+  Svc.Prefs.set("log.appender.file.logOnError", true);
+  log.info("TESTING");
+
+  // Ensure that we report no error.
+  Status.login = MASTER_PASSWORD_LOCKED;
+  do_check_false(ErrorHandler.shouldReportError());
+
+  Svc.Obs.add("weave:service:reset-file-log", function onResetFileLog() {
+    Svc.Obs.remove("weave:service:reset-file-log", onResetFileLog);
+
+    // Test that error log was written.
+    let entries = logsdir.directoryEntries;
+    do_check_true(entries.hasMoreElements());
+    let logfile = entries.getNext().QueryInterface(Ci.nsILocalFile);
+    do_check_eq(logfile.leafName.slice(0, LOG_PREFIX_ERROR.length),
+                LOG_PREFIX_ERROR);
+
+    clean();
+    run_next_test();
+  });
+  Svc.Obs.notify("weave:service:login:error", {});
+});
+
 // This test should be the last one since it monkeypatches the engine object
 // and we should only have one engine object throughout the file (bug 629664).
 add_test(function test_engine_applyFailed() {
   let server = sync_httpd_setup();
 
   let engine = Engines.get("catapult");
   engine.enabled = true;
   delete engine.exception;