When you receive a drawing that was last saved in AutoCAD and you want to plot it in AutoCAD LT for Mac running in macOS, you will find that you can't locate the Plot Styles folder to add the acad.ctb color dependent plot style table.
With the acad.ctb available, then the plot settings dialog will use the line settings that the drawing last used. In AutoCAD LT, the default color dependent plot style table is named acadlt.ctb so it can't find acad.ctb.
Typically you would browse to the plot styles folder here to add any new plot style tables:
/Users/<username>/Library/Application Support/Autodesk/roaming/AutoCAD LT 2013 Standalone/R19.0/enu/Plotters/Plot Styles
Note: You can also double click the Plot Style Table Search Path listed in Options/Preferences as shown here:
Starting with Lion, Apple has hidden the Library folder under the current user name, presumably for security reasons. To regain easy access to the subfolders, including AutoCAD and AutoCAD LT's support folders, you can either temporarily gain access to them using Apple's recommended method detailed here:
Unhide the Library Folder, the Apple Way
- With either the desktop or a Finder window as the frontmost application, hold down the option key and select the Go menu.
- The Library folder will be listed as one of the items in the Go menu.
- Select Library, and a Finder window will open showing the contents of the Library folder.
- If you close the Library folder's Finder window, the folder will once again be hidden from view.
...or you can permanently turn on access to the Library folder using the Terminal application, which is the Mac equivalent of the CMD prompt for Windows. The Terminal app can be found in the Applications folder. If you enter the following command chflags nohidden ~/Library/ in the Terminal it will show the Library folder.