Converting shape Polyline-M to Polyline using ArcGIS Desktop?

Just use an ArcToolbox command, such as "Feature Class to Feature Class"

Click the "Environments..." button

In the "M Values" and/or "Z Values" just specify the Output as "Disabled"

While jeb's answer led me to this answer, his lacked a little bit of detail that I would have liked in an answer. This is the easiest way I found to convert PolyLine-M to Polyline.

1. Open your ArcToolBox
2. Open "Conversion Tools"
3. Expand "To Shapefile"
4. Run "Feature Class to Shapefile (multiple)"
5. Select your input shapefile
6. Choose your destination folder in which your new shape file will be created. IE. "C:\"
7. Click on the Environments button
8. Expand "M Values" and choose to disable them (This is what removes the M values so that it will become a regular polyline shapefile)
9. Click create, and your new file will be created in whatever destination folder you chose

There are several ways to achieve the above. But this ultimately seemed the easiest in the long run.