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, you need to install the 32bit version of AutoCAD LT 2015 instead – to solve the problem, simply follow these instructions.

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 AutoCAD 2005 on Windows 11

Follow these instructions to solve issues around installing/running your legacy AutoCAD 2005 on Windows 11

Ransomware Protection Windows 11 and AutoCAD

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 2005 

A quick word of advice: please follow the instructions below precisely as documented including using the same folder names and paths. This will significantly reduce the risk of having any problems…
  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. Start the Longbow Converter tool
    1. Insert your AutoCAD 2005 CD into your CDRom drive
    2. Select the 2nd tab named “Old AutoCAD Installer Reviver
    3. Using the “…” button, pick your AutoCAD CD
    4. Click “Run Old Installer
      1. Read and follow all the prompts
      2. Once the AutoCAD setup starts, stop and read the next step…
  5. In the AutoCAD setup program, navigate through each setup dialog as normal, with these exceptions…
    1. When you arrive at the installation folder path setup dialog…
      1. **it’s vitally important to make sure you install to c:\acad2005 (not Program Files (x86)\AutoCAD 2005)**. Now install…
      2. While installing…
        1. If you see an error in install “.NET Runtime Optimization Service has stopped working” – simply ignore by clicking the “Close Program” button
        2. When a message box appears warning that “64bit .NET Unavailable” – simply click OK to carry on and install AutoCAD as normal – this does not affect anything.
        3. Do not reboot if asked to do so
      3. Once installed
        1. Do not reboot if asked to do so
        2. Make sure to fully close the setup program when the installation is complete.
        3. Switch back to the Converter app and make sure it’s completed the final stage of processing using the “Old AutoCAD Program Reviver” tab – it should display “SUCCESS!” – if not switch to the “Old AutoCAD Program Reviver” tab, pick the c:\acad2005 folder and click “Fix Old Program”
  6. Finally, reboot your PC and run your AutoCAD as normal
    1. NOTE: When starting AutoCAD, if you see a warning dialog when you run saying “This program has known compatibility issues
      1. Click “Don’t show this message again
      2. then click “Run the Program…

Installing AutoCAD 2005 Sp1

To install the sp for your AutoCAD…
  1. Download your AutoCAD 2005 Sp1
  2. Copy the service pack exe installer to folder path c:\Autodesk\sp
  3. Start the Converter App
    1. select the 3rd tab named “Old AutoCAD Program Reviver
    2. Using the “. . .” button, pick the c:\Autodesk\sp folder
    3. click “Fix Old Program“.
  4. Now you can run the service pack exe installer from Windows explorer 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