AutoCAD Is Unable To Load Ac1st16.dll & Other Dll Files

Cal Newport
Cal Newport Last Updated: May 19, 2022


Software: Windows 7, 8 & 10 | Last modified on 2018-06-18


When attempting to launch the AutoCAD software, an error occurs stating that ac1st16.dll or other dll files are missing and cannot be loaded. Sometimes AutoCAD installs the required DLLs in the Autodesk Shared folder, but needs them in the AutoCAD LT folder.

[Solution 1] Copy all data to another folder


  1. Close all AutoCAD software and restart the computer.
  2. Open C:\Program Files (x86)\Common Files\Autodesk Shared and copy all data from this folder to C:\Program Files (x86)\AutoCAD LT *year* (replace *year* with the version number)
  3. Open the AutoCAD software and it should be able to launch.

[Solution 2] Reinstall the AutoCAD software


  1. Open the Control Panel and click Programs & Features.
  2. Select the AutoCAD software and click Uninstall.
  3. Let the process finish and restart the computer.
  4. Download and install the AutoCAD software.

Cal Newport
Written by

Cal Newport

Cal Newport is Provost’s Distinguished Professor of Computer Science at Georgetown University, and the author of seven books. His ideas and writing are frequently featured in major publications and on TV and radio.


0 ratings

Related articles