diff --git a/src/managers.jl b/src/managers.jl
index fccc5ea..603e26d 100644
--- a/src/managers.jl
+++ b/src/managers.jl
@@ -347,7 +347,7 @@ function launch_on_machine(manager::SSHManager, machine::AbstractString, cnt, pa
 
         any(c -> c == '"', exename) && throw(ArgumentError("invalid exename"))
 
-        remotecmd = shell_escape_wincmd(escape_microsoft_c_args(exename, exeflags...))
+        remotecmd = shell_escape_wincmd(escape_microsoft_c_args(exename, exeflags...)::AbstractString)
         # change working directory
         if dir !== nothing && dir != ""
             any(c -> c == '"', dir) && throw(ArgumentError("invalid dir"))