# A. NoMachine NX is reporting "connection" or "access error" messages

Sorry to say, our NoMachine NX GUI login can be very particular at times. You may receive connection errors, access denied errors, or the like. A few simple steps may remedy the problem:

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# B. I launched an application in NoMachine or the terminal. Why isn't it running?

There are several reasons why an application may not appear to be running:

• All of the licenses for the application may be in use by others.
• More commonly, you may have reached the resource limit on your account (# of CPUs or memory limit).
• If the compute grid is busy, there many not be enough RAM or CPUs on any of the compute nodes to run your application.

Open a terminal session and type bjobs on the command line (...

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# B. I need an interactive session with more RAM. How do I do this?

NoMachine provides convenient access to interactive sessions via the drop-down menus. Choosing one item runs a 'wrapper' script with default parameters to start your sessions (for that reason, we call them default submission scripts). But if you need a larger RAM footprint than provided, you must write a custom submission script (see this document), which provides at least the queue name, the program to run, and your requested RAM amount. For example, to...

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# C. How can I run an older version of a software title?

For simplicity and ease of use, only the latest versions are offered the in NoMachine drop-down menus and via the wrapper scripts. But there are ways that you can still run older versions.

Although we may not make wrapper scripts (and hence drop-down menus on which these are based) for all software titles, the older versions of the software are still installed on the cluster.

In order to run jobs with these older versions, you will need to know the path to the program and use that in a custom LSF job submission that you must write. Please see our...

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# C. How can I use the latest version of R or RStudio?

The current installation on the HBS compute grid for RStudio is v0.99.99 and its companion R version is v3.1.2, the latest that this version of RStudio can fully support. We are aware that these are not recent versions: this is an unfortunate result due to limitations of the operating system (OS) and how software installations are managed on the compute grid. We are currently working with HBS IT find a solution to overcome this limation, which we hope to have remedied by late fall 2018.

In the meantime, if you require a more current version of R within this version of...