Check if the ALM service is running when this problem occurred. Thereafter update you ALM (Automation License Manager) software to the newest version. Make sure you do a proper PC restart (not a quick restart!). Test again.

Contact Siemens by registering a Support Request if you confirmed that there is still a problem. They will ask for the full logs. There are some diagnostics they need to have you run also. Please let us know the result.

Good luck.

What have you tried so far?

Installed latest V20 update?

Updated to latest ALM (v6.2 SP3 last I looked).

Nothing?

U_06e92547-d61b-4f88-863c-39ff4b152e76

To Imariani : 

Hello,

Have you found a solution? 

I have exactly the same problem and the same error log.

Ty

0_Einstein

What have you tried so far?

Installed latest V20 update?

Updated to latest ALM (v6.2 SP3 last I looked).

Nothing?

[ 18 September 2025 ] Automation License Manager V6.2 SP4.
Software for the authorization and licensing of SIMATIC products. (ALM)

First off, zip up / archive your v20 project and submit to Siemens Support using the Support Request tool.  Siemens needs to know about projects that crash, especially for their most recent version so they can FIX IT!

After that...

Try the following:

With the V20 project open and with no blocks open, try right-click on the PLC, select "hardware - rebuild all" or the equivalent.

If HW-rebuild-all crashes:

Reopen the project, then "Save-As" a new project so you have a reference project in case you need to get back to this point.

With the newly saved project still open, use it as a reference for the hardware configuration.

Now, I recommend building the hardware configuration again - from scratch with 2 tia portal's open so you can manually transfer settings between the new manually reconstructed project.

If the HW-rebuild-all does not crash:

With the V20 project still open and with no blocks open, try right-click on the PLC, select "software - rebuild all".

If it does not crash, "Save-As" a new project so you have a reference project in case you need to get back to the point where both HW and SW compile / rebuild all works.

With the newly "Save-As" project open, try opening the problem FB.

If both HW/SW rebuild-all worked and the problem FB still crashes V20, refer to the HW rebuild process above to build a "new" project from scratch in a 2nd TIA Portal session (window).

First, in the reference project, select every block (OB/FB/FC) that you can open without crashing TIA Portal, and drag over to the "new" project.  Repeat for PLC Tags, UDTs, TOs, and so on.  Drag-n-drop as much as you can from the software portion of the project.

In the "new" project, make sure it will compile both HW and SW (rebuild all).  You may get errors for any calls to blocks that are not present.  You can temporarily remove those block calls to get a successful software compile/rebuild.

Now we hope your FBs are SCL so you can export them from the original project, then import them into the "new" project.  If not, you may need to look at TIA Openness to export and import those blocks.

At this point, I think you may have an answer from Siemens Support from your earlier submitted Support Request and they will have found and fixed the problem and returned a working project to you.

U_ea558d57-c90a-40f9-ac3a-7e94d8e4c1ce

Hello, 

Thank you for your feedback.

 I installed ALM6.2 SP4 and the problem is the same.

I am using TIA V20 SP3, it is the latest version.

Ty

Have you tried with another PC. Or ask a friend to check the project.

Best to contact Siemens. Use the “Support Request” link. The support team will be able to check the integrity of the project file.

Am I to understand that you can open everything including FB/FC/OB in other projects, TIA Portal works fine, but in this one problem project, it crashes when you open any program block?

Or, does TIA Portal work perfectly until you try to open any program block in any project?

Try using a local windows admin account to create a new user (using COMPMGMT.msc - run as admin).  Assign a password you will remember since it will become your new "test" account.

Shutdown tia portal, and log out.

Login to that new user account.

Open tia portal v20.  Now create a default project.  Save it to the default location.

Add a PLC of your choice.

Open OB1.

Does it crash with this new user account?

U_ea558d57-c90a-40f9-ac3a-7e94d8e4c1ce

Thank you for the feedback and advice 0-Einstein,

But this is not a project issue.

I have opened other projects and even created a new one, and as soon as I open an FC, FB, or OB in any language, TIA crashes.