diff --git a/provisioner/powershell/provisioner.go b/provisioner/powershell/provisioner.go
index 0dccf78e7..3e7d43fc8 100644
--- a/provisioner/powershell/provisioner.go
+++ b/provisioner/powershell/provisioner.go
@@ -147,11 +147,11 @@ func (p *Provisioner) Prepare(raws ...interface{}) error {
 	}
 
 	if p.config.ExecuteCommand == "" {
-		p.config.ExecuteCommand = `powershell -executionpolicy bypass "& { if (Test-Path variable:global:ProgressPreference){$ProgressPreference='SilentlyContinue'};. {{.Vars}}; &'{{.Path}}';exit $LastExitCode }"`
+		p.config.ExecuteCommand = `powershell -executionpolicy bypass "& { if (Test-Path variable:global:ProgressPreference){set-variable -name variable:global:ProgressPreference -value 'SilentlyContinue'};. {{.Vars}}; &'{{.Path}}';exit $LastExitCode }"`
 	}
 
 	if p.config.ElevatedExecuteCommand == "" {
-		p.config.ElevatedExecuteCommand = `powershell -executionpolicy bypass "& { if (Test-Path variable:global:ProgressPreference){$ProgressPreference='SilentlyContinue'};. {{.Vars}}; &'{{.Path}}'; exit $LastExitCode }"`
+		p.config.ElevatedExecuteCommand = `powershell -executionpolicy bypass "& { if (Test-Path variable:global:ProgressPreference){set-variable -name variable:global:ProgressPreference -value 'SilentlyContinue'};. {{.Vars}}; &'{{.Path}}';exit $LastExitCode }"`
 	}
 
 	if p.config.Inline != nil && len(p.config.Inline) == 0 {