If your SmartSDR DAX Drivers Puke or Get Scrambled

What to do if your SmartSDR DAX Drivers Puke or Get Scrambled?

Windows Updates have been playing havoc with SmartSDR for several years.

Certain Updates (1803, 1811) have jinxed a large percentage of users machines, but other seemingly routine updates can make things act funny too. Some cases you can fix this stuff yourself. DAX drivers are the usual victim of these Windows Updates.

There are some ways to do your own first aid to fix the DAX problems, but they are not just a double-click on a fix-it-program.

Always, if you really get stumped you can open a Help Ticket at FlexRadio ( http://www.flexradio.com – then go to Support, then HelpDesk).

This compilation is cut & paste mashup from the FRS (FlexRadio Systems) Website, Community Forums and Emails. It is current as of SmartSDR 2.4.9 on 20 January 2019.

YMMV on how effective this all is, and again remember you can ask FRS for help if you’re not comfortable trying self-help.


Simple DAX Naming Sickness can be cured by renaming DAX drivers:

FRS Published some notes on how to do this:  https://community.flexradio.com/flexradio/topics/most-common-fix-for-dax-driver-errors-in-windows-spring-update-1803-you-can-do-this


Bad DAX Stuff Might Respond to a DAX Removal and Reinstall process:

Sort of middle ground fix is to remove SmartDAX and Reinstall it on its own.

Again FRS offers some notes: https://helpdesk.flexradio.com/hc/en-us/articles/204017069-How-to-Manually-Re-Install-DAX-Drivers


DAX removal and reinstall is pretty straight forward.  The FRS HelpDesk Article does have all the information, but it can be distilled down into something understandable, rather than doing it by rote.

You also can do this from the normal Windows GUI rather than pretending you still remember the DOS file structures and navigation.

Here is the GOAL – for each version of SmartSDR you need to get to the DAX drivers directories, and run two batch files.  There are four DAX driver directories for a version of SmartSDR.  One batch file removes that part of DAX and the second batch file puts a new copy of that part of DAX in place.  Best to run these as Administrator (the Right Click thing) and you repeat until your have erased and replaced all the DAX parts.


  1. Export your profiles and make any backups you might feel needed.
  2. Remove any unused versions of SmartSDR, and select DAX removal when you do it.
  3. Now you should be down to just the versions of Software you are intending to use.  In my case it was SmartSDR versions 2.4.9 and a test version I wanted to keep.
  4. Using file explorer navigate to the 64-bit Drivers directory for the lowest verison but highest release numbered version you are keeping. (Like Version 2 but but then 2.4.9 was the highest point numbers.)  You don’t have to worry so much about the issue of various DAX version levels if you don’t want to run Version 1 software and/or are not part of the test team.
  5. There are FOUR sub-directories that are going to be touched:
    1. IQ_DAX
    2. RXAudio_DAX
    3. TXAudio_DAX
    4. MICAudio_DAX
  6. Navigate to each of these four sub-directories and RIGHT-CLICK to “Run as Administrator” in Uninstall then Install order:
    1. Uninstall Batch File
    2. then the Install Batch File
  7. When you have run the Eight (8) Batch files for the version of SmartSDR you MAY have to repeat the exercise for the highest point numbered SmartSDR of any other major version level you intend to run.  In fact you just might have to repeat for ANY additional versions of SmartSDR you are keeping, as the dependencies of DAX versions to SmartSDR versions isn’t exactly easy to sort out.
  8. Reboot your machine and test the results.

YMMV but it worked the treat on the Win10Pro box that I let get screwed up, though I did have to repeat the exercise when I deleted unneeded SmartSDR versions after the first time I fixed things, as those deletions seems to re-scramble DAX again.

You can Remove a version of SmartsSDR from the Windows control panel, as in the end it will call exactly the same script that would have been used if you did the Command Window routine.

Oh, as an example of just one of the directories you will be running a batch file would be:

“C:\Program Files\FlexRadio Systems\SmartSDR v2.4.9\64-bit Drivers\IQ_DAX\”

An example Uninstall Batch file is “SmartSDR_IQ_DAX_uninstall.bat”

An example Install Batch file is “SmartSDR_IQ_DAX_install.bat”

FlexRadio’s naming conventions are consistent.

For Really Bad DAX Stuff it is Deleting the whole SmartSDR ecosystem that is usually the fix:

(Remember to Export Profiles and copy down your CAT/DAX Information)

The FRS Guide to Completely Deleting SmartSDR (along with SmartDAX, SmartCAT and VSP) is:

(Treat this routine like a Checklist and follow it carefully)

There are two sub-routines to this process which are at:

First Sub-Routine – Deleting SmartCAT and VSP (Virtual Serial Ports):
Download the SmartCAT Manual from http://www.flexradio.com/downloads/smartsdr-cat-user-guide-pdf/
(What you need is on Pages 4 through 7, and if you have a legacy CAT version on your machine Page 46. I printed out only those pages.)

Second Sub-Routine – Dealing with (any) Ghost Ports:
(If you Print you only need Page 1)

What to do Next:

Not explicitly covered is after a Reboot, use the normal SmartSDR Install Package (download from http://www.flexradio.com ) to reinstall all the parts of the SmartSDR ecosystem (including VSP, SmartCAT, SmartDAX and of course SmartSDR itself).


  • Process is for Windows.
  • VSP is a background service you wouldn’t otherwise get involved with.
  • Some Antivirus & Firewall setups cause problems, so you may need to disable them.
  • Everything looks to work well on Win7/Win10, but you may have varying levels of problems with 2000/Win8/Other Windows versions.


  • Consider creating a Restore Point.
  • Some folks report good success using software like REVO to clean up their registry while doing these processes.
  • Also FRS Recommends a Complete Uninstall before letting Windows do Updates.


GL & 73


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