AutoCAD LT 2015 on Windows 11 – FATAL ERROR: acismobj20.dbx

If you are running AutoCAD LT 2015 on Windows 11 and you receive this error…

FATAL ERROR: (0x7ffb71c40005) C:\Program Files\Autodesk\AutoCAD LT 2015\acismobj20.dbx

The issue is that you are running 64bit AutoCAD LT 2015 on Windows 11, this is an old version of AutoCAD which is easily affected by Windows Updates pushed by Microsoft. You need to install the 32bit version of AutoCAD LT 2015 instead as it is not as easily affected by the latest Windows components. To solve the problem, you must first uninstall your existing AutoCAD LT 2016 (do not install along side as it will not work) and then follow these instructions to install the 32bit version (which is much more reliable and actually runs faster)

Copyright 2023 (c) Longbow Software

Installing 32bit AutoCAD LT 2015 on Windows 11

These instructions solve issues around installing/running your old AutoCAD 2015 on 64bit Windows 11. Some common issues are error messages like these

  • “This operating system is not supported by AutoCAD LT® 2015”
  • “You cannot install this product on the current operating system”
  • “You are attempting to use a 32-bit installer on a 64-bit operating system”
  • “This is a 32-bit AutoCAD LT® 2015. It cannot be installed on 64-bit Windows”
  • FATAL ERROR: (0x7ffb71c40005) C:\Program Files\Autodesk\AutoCAD LT 2015\acismobj20.dbx

You can automatically solve these problems using our Longbow Converter App, it fixes and manages the AutoCAD LT 2015 installation so that you can be up and running again… Follow these instructions:

Ransomware Protection Windows 11 and AutoCAD

Just before we start note that Windows 11 comes with a Ransomware Protection which includes Controlled Folder Access. Controlled folder access blocks applications from writing to your Documents, Pictures, Videos, Music, Public and Favorites folders. AutoCAD versions all the way to AutoCAD 2021 write to certain user Public folders and are therefore blocked by this feature. This can cause issues with all sorts of things including activating your AutoCAD license and even running AutoCAD. Ransomware Protection is an important feature of Windows 11 but it will affect your AutoCAD unless you allow AutoCAD and its dependent applications access to the controlled folders.

How to install AutoCAD LT 2015

  1. If you don’t yet have a copy of the Longbow Converter App you can purchase it here or click on the download link we sent you via email in order to download the Converter App to your PC.
  2. Before installing the Converter App, make sure the files downloaded from our site are not blocked by Windows SmartScreen… Windows 11 is finicky, click the TLC zip first to make sure it’s fully selected then Right+click the file and select Properties. Be sure to check the Unblock checkbox as shown below and Click OK…
  3. Double click the zip file to open it and install the TLC application as normal. By the way, TLC stands for The Longbow Converter
  4. Obtain your purchased copy of the Longbow Converter here
  5. Start the Converter App and note the user interface
  6. Select the 1st tab named “AutoCAD 32bit Installer Converter
    1. Using the “. . .” button, selection your AutoCAD installation CD
    2. Next, click the “Convert button and follow instructions
  7. Once the conversion process is complete
    1. click Install/Run Setup to start setup
    2. Simply install as normal, remembering to…
      1. Close the setup program when the installation is complete.
      2. Back in the Converter app and make sure it has completed the final stage of processing using the “Old AutoCAD Program Reviver” tab – it should be green stating “SUCCESS”
  8. Now run your AutoCAD as normal

Troubleshooting

  1. If you have crashing problems using the File->Open or File->Save dialogs inside of AutoCAD please read this blog entry on the File->Open or File->Save Crash in AutoCAD
Copyright 2022 (c) Longbow Software

Installing 32bit AutoCAD LT 2015 on Windows 7, Windows 8 and Windows 10

NOTE: This blog post specifically solves issues related to these error messages on installation…

  • “This operating system is not supported by AutoCAD LT®”
  • “You cannot install this product on the current operating system”
  • “You are attempting to use a 32-bit installer on a 64-bit operating system”
  • “This is a 32-bit AutoCAD LT® 2015. It cannot be installed on 64-bit Windows”

NOTE: These steps do not bypass normal Autodesk licensing/authorization, you should expect to use your own serial numbers in the normal way.

Installing AutoCAD LT 2015 32bit on Windows 7, Windows 8, Windows 8.1 or Windows 10 64bit can be very easily defined in these short steps.

  1. Obtain your copy of the Longbow Converter here
  2. If you have CDs (if not check (3) below):
    1. Using Windows Explorer, copy Disk 1 of your AutoCAD LT 2015 CD to your hard drive, to a folder path c:\Autodesk\AutoCADLT2015
    2. If you have more CD’s, copy them all directly over the top of Disk 1, overwrite all files in your previously copied c:\Autodesk\AutoCADLT2015 folder
  3. If you have a single self extracting exe downloaded from Autodesk called something like AutoCAD_LT_2015_English_Win_32bit.exe
    1. Simply run the exe, it will ask to unzip to a folder inside of c:\Autodesk, make a note of the folder for later use (we’ll refer to it from here as c:\Autodesk\AutoCADLT2015), now click OK. Wait until all of the files have extracted, when they do, the AutoCAD LT 2015 setup will automatically launch – simply close it and move to the next step.
  4. Now, start the Longbow Converter tool, select the 1st tab named ‘AutoCAD 32bit Installer Converter
    1. pick the c:\Autodesk\AutoCADLT2015 folder
    2. click the ‘Convert‘ button.
  5. Once the conversion process is complete
    1. Click ‘Install/Run Setup‘ to start setup
    2. Install as normal.
  6. Windows 8, Windows 8.1 and Windows 10 users: Once the installation process is complete…
    1. go back to the Converter, select the 3rd tab named ‘Old AutoCAD Program Reviver
    2. Pick the newly installed C:\Program Files (x86)\Autodesk\AutoCAD LT 2015 folder
    3. Click ‘Fix Old Program‘.
  7. Now you can happily run your AutoCAD LT 2015 32bit on Windows 7, Windows 8 and Windows 10!

Troubleshooting:

– If you are unable to activate your product, or the activation process crashes:

– If you have crashing problems using the File->Open or File->Save dialogs inside of AutoCAD please read this blog entry on the File->Open or File->Save Crash in AutoCAD

Copyright 2016 (c) Longbow Software