diff --git a/perfkitbenchmarker/pkb.py b/perfkitbenchmarker/pkb.py
index aa5cdfcf87..a1220082f7 100644
--- a/perfkitbenchmarker/pkb.py
+++ b/perfkitbenchmarker/pkb.py
@@ -163,7 +163,7 @@
                     'Specify a proxy for FTP in the form '
                     '[user:passwd@]proxy.server:port.')
 
-MAX_RUN_URI_LENGTH = 10
+MAX_RUN_URI_LENGTH = 8
 
 
 # TODO(user): Consider moving to benchmark_spec.
diff --git a/perfkitbenchmarker/virtual_machine.py b/perfkitbenchmarker/virtual_machine.py
index 8b573792ff..0e535e94fa 100644
--- a/perfkitbenchmarker/virtual_machine.py
+++ b/perfkitbenchmarker/virtual_machine.py
@@ -93,7 +93,7 @@ def __init__(self, vm_spec):
     super(BaseVirtualMachine, self).__init__()
     with self._instance_counter_lock:
       self.instance_number = self._instance_counter
-      self.name = 'perfkit-%s-%d' % (FLAGS.run_uri, self.instance_number)
+      self.name = 'pkb-%s-%d' % (FLAGS.run_uri, self.instance_number)
       BaseVirtualMachine._instance_counter += 1
     self.project = vm_spec.project
     self.zone = vm_spec.zone
diff --git a/perfkitbenchmarker/vm_util.py b/perfkitbenchmarker/vm_util.py
index 269e01ef95..31cff55f91 100644
--- a/perfkitbenchmarker/vm_util.py
+++ b/perfkitbenchmarker/vm_util.py
@@ -686,7 +686,11 @@ def _RegisterDStatCollector(sender, parsed_flags):
 
 def GenerateRandomWindowsPassword(password_length=PASSWORD_LENGTH):
   """Generates a password that meets Windows complexity requirements."""
-  special_chars = '~!$%*_-+=\\[]:.?/'
+  # The special characters have to be recognized by the Azure CLI as
+  # special characters. This greatly limits the set of characters
+  # that we can safely use. See
+  # https://github.com/Azure/azure-xplat-cli/blob/master/lib/commands/arm/vm/vmOsProfile._js#L145
+  special_chars = '*!@#$%^+='
   password = [
       random.choice(string.ascii_letters + string.digits + special_chars)
       for _ in range(password_length - 4)]