RunningLow – PowerShell script to check for disk space and send e-mail A free PowerShell script that will check for low disk space on local and/or network drives and servers and send e-mail to System Administrators

Event Viewer: come inviare notifiche e-mail dal Registro Eventi con uno script Powershell

Today I would like to share with our readers RunningLow, a simple yet effective PowerShell script I coded a while ago to get to know when one of my servers is running low of disk space.

Whoever works with physical and/or virtualized Windows Servers is well aware of the importance of keeping this constantly under control: as soon as a server runs out of disk space it will be unable to fullfill a number of tasks, such as: create temporary files, store data on a database, performing system maintenance / backup / updates, create or update web sessions – assuming they are handled through I/O – and so on. Things can be even worse for those servers who host DBMS services such as MySQL and MS-SQL, as the sudden I/O unavailability could cause non-trivial damages to indexes, filesystem-based tables and data integrity.

The main purpose of RunningLow is to prevent all that: it will check one or more local and/or network drives to see if their available free space went under a certain quota, and send a customizable alert to one or more e-mail addresses if that’s the case. I know, there are A LOT of admin suites and maintenance software that could be easily configured to the same thing: even Piriform’s CCleaner PRO does that! However, if you don’t have the money, the time or the amount of system resources required to install these apps, you might find out that this lightweight alternative could be worth a shot.

UPDATE: RunningLow 1.1 (and later) added support for network drives and a whole set of CLI configuration parameters: be sure to check it out!

Source Code

Anyway, here’s the script source code:

Copy/paste it into a text file, save it to RunningLow.ps1 (or any other name) and you should be set. Alternatively, you can also download the latest version from the project’s official GitHub repo.


The first ten or so lines host the configuration settings, which you should change accordingly to your needs and depending to your specific scenario. The most important thing to understand is the first line: as we can see, we can either specify an array of drives – including network drives, as long as they’re permanently mapped to a local drive letter – or set a null value: if we go for the latter, the script will check all local drives.

The comments should be enough to guide you through this required part: however, if you need further assistance, you can use the comment section of this post to submit your query and I’ll do my best to help you with that.


As soon as you’re done with the configuration, you can test the script from the standard Windows Command Prompt with the following command:

… Or by typing


from a PowerShell prompt.

As soon as you hit ENTER, you should see something like this:

RunningLow - PowerShell script to check for disk space and send e-mail

… Meaning that everything went ok.

Sending E-Mail Alerts

Needless to say, you should then edit the script, raise the $minSize value to a ridiculously high amount (such as 5TB) and run another test to ensure that the e-mail alerts will actually be sent:

RunningLow - PowerShell script to check for disk space and send e-mail

… That’s it.


It goes without saying that the script should not be launched manually: the best thing we can do to ensure that it will be executed on regular basis is to create an appropriate entry in the Windows Task Scheduler. In the example below, RunningLow will be executed once a day at noon:

RunningLow - PowerShell script to check for disk space and send e-mail

In the New Action window you can either insert the full execution statement (including parameters) in the Program/script textbox, or use the Add arguments (optional) textbox: the script will work either way. Similarly, you can specify the full path of the  RunningLow.ps1 file within the -File parameter or put it into the Start in (optional) textbox, just like we did in the above screenshot.

IMPORTANT: In the scheduled task General tab, be sure to activate the options Run whether the user is logged on or not and Run with highest priviledges, otherwise the script would run only if there’s a logged-in user during the execution time.

Be sure to test it again – by setting an insanely high $minSize – on the server as well, to be sure that there are no firewalls or other restrictions that would block the e-mail alerts.

Well, that’s it for now: I sincerely hope that you will enjoy having RunningLow on your servers just like I do!

Useful Links

Fork me on GitHub


About Ryan

IT Project Manager, Web Interface Architect and Lead Developer for many high-traffic web sites & services hosted in Italy and Europe. Since 2010 it's also a lead designer for many App and games for Android, iOS and Windows Phone mobile devices for a number of italian companies. Microsoft MVP for Development Technologies since 2018.

View all posts by Ryan

17 Comments on “RunningLow – PowerShell script to check for disk space and send e-mail A free PowerShell script that will check for low disk space on local and/or network drives and servers and send e-mail to System Administrators

    1. use this to convert to MB:

      2 is number of decimal

      Replace MB with KB, GB, or TB if you’re trying to convert other units

    2. I would just do this:

      Anyway, the new version already does the conversion either in the CLI screen and in the alert e-mail.

  1. Hi Ryan,

    just wanted to give you a shout to say thanks. Very useful and concise. I personally did away with the email notification, and simply initiated a recursive delete of a folder I know has an ever growing set of files in it over time.

  2. Hello Guys,
    How can I do, that this script check to other servers too. For example reads a computer lost from txt file.
    Thank you very much your help!

    1. Hi there,
      we just published the new version on GitHub with some new features, including the LAN/network support through hostname or IP address (see the -hosts parameter): be sure to check it out!

  3. I Am getting this error-pls help on this
    Exception calling “Send” with “1” argument(s): “Failure sending mail.”
    At E:\writable\OneDrive\Desktop\Test\RunningLow-master\RunningLow.ps1:74 char:9
    + $smtp.send($message);
    + ~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : SmtpException

    1. Hello there,
      check your powershell version by executing the following line from a command-line:

      Tell me which version you’re running: you could have to upgrade it.

      Here’s the SmtpClient namespace docs: as you can see, the .Send() method can accept a single parameter.

  4. -noNewLine : The term ‘-noNewLine’ is not recognized as the name of a cmdlet, function, script file, or operable program. Check the
    spelling of the name, or if a path was included, verify that the path is correct and try again.
    At C:\Users\dparmar\Desktop\Test.ps1:104 char:48
    + Write-Host(“: sending e-mail…”); -noNewLine
    + ~~~~~~~~~~
    + CategoryInfo : ObjectNotFound: (-noNewLine:String) [], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException

    we are getting this error

    1. Maybe you’re using PowerShell v4 or lower: either upgrade your PS to v5+ or just remove that attribute (or use the -join attribute).

  5. Brilliant script. Would it be possible to tweak this so that the e-mail is sent if the free space is lower than certain percentage rather than free disk space in GB?

    1. Sure, why not?

      Here’s how you calculate the $y% of $x:

      Therefore, instead of doing this:

      do this:

      Where $y is the min free percentage you want to check.

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