官方描述及解答：
Local Applications Cannot Be Monitored (Error Dialog On Startup)
Description: An
error dialog saying that local applications cannot be monitored is shown immediately after VisualVM startup.
Resolution: This can happen
on Windows systems if the username contains capitalized letters. In this case, username is UserName but
the jvmstat directory created by JDK is%TMP%\hsperfdata_username.
To workaround the problem, exit all Java applications, delete the %TMP%\hsperfdata_username directory
and create new %TMP%\hsperfdata_UserName directory.
即：把%TMP%\hsperfdata_username文件删除，重新建立%TMP%\hsperfdata_UserName文件（username为具体的用户名，区分大小写）。
%TMP%：%TMP%为用户环境变量，在cmd下echo %TMP%可以查看具体路径，或者直接在地址栏输入%TMP%直接进入文件目录。
username：cmd下echo %USERNAME%即可查看用户名。