Lost Linetype - defaulted back to continuous

[dmerrittHQE4L]

So I have been working in a project that has 12 different P&ID's and have not had any issues when creating new sheets etc with linetypes. Today while working, my PC went to sleep and when I returned to the drawings all the drawings (including the not opened ones) defaulted back to continuous lines. In the project setup they are setup to be by layer. When you select a line that is messed up it is blank in the Properties Window. The instrument lines are setup to drawn per specified linetype. I have tried to Purge, used a different version of P3D, had other users open the files, restore the drawings from yesterday, but nothing seems to work.

 

 

 

 

[h_eger]

@dmerrittHQE4L ,

Did you also change the assignment of the line types in your P&ID template file before you created the P&ID?
Unfortunately, changing the line type only in the project setup and in the P&IDs themselves only brings limited success.

[dmerrittHQE4L]

@h_eger Thanks for the response. Unfortunately we did not, its the same starter template/.xml file. I am using '25 so not sure if maybe there is a bug or not then. I may switch back and use an older version and fix all the current .dwgs and layers.

[h_eger]

it is about the P&ID template in which the layers must also be customised according to your wishes

[dmerrittHQE4L]

@h_eger I checked this out and the template drawing is correct with the linetypes. Hopefully this doesn't happen again after its fixed.

[h_eger]

@dmerrittHQE4L ,

Please create a support case at Autodesk AutoCAD Plant.
There is a bug where the linetype is disabled and no longer displayed in the properties window or when the linetype is displayed it is empty and cannot be changed.

[dmerrittHQE4L]

@h_eger I had opened a ticket and it is an issue that other users are also experiencing, they did a write up and submitted to Autodesk so they can hopefully fix this in their next update.

[h_eger]

@dmerrittHQE4L ,

many thanks for that

[GCM_S_Hotte]

Hi,

We're having this issue since more than a month, reported to Autodesk and still waiting for an answer and a fix since we can't deliver our drawings as we need. And it messing up all the existing drawings.

Thanks,

SH

[pendean]

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@GCM_S_Hotte wrote:

...reported to Autodesk and still waiting for an answer and a fix...

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Reported? Did you by chance open a support ticket and talk with a person and allowed them access to your PC and files?

[GCM_S_Hotte]

Yes, I had a remote session to show Autodesk team what's going on. The case is under investigation.

[milosz_mirkowski]

I have the same problem.

A temporary solution after losing line formatting is to draw a new, auxiliary line, which should now display correctly and have the style you applied.

Then select all the lines you want to reformat, e.g. with qselect, along with the line you drew. Then the disappearing Linetype window will appear and the properties should display as *VARIES* for the selected lines. You can then change the style from the drop-down list for all lines, including those with lost formatting.

It doesn't solve the problem, but you can at least publish/print.

[eystein.killiVM42H]

I have the same problem. Using P3D 2025 and had this problem for at least two months. Hope for a quick update on this issue!

Regards Eystein

[h_eger]

@eystein.killiVM42H ,

please contact AutoCAD Plant 3D Support and report this problem as a support case.

[tim_proemper7FMU6]

Just encountered this problem as well. After restarting P3D, the linetype property is just gone and all signal lines are reverted to continuous.

How has this not been fixed yet?

[GCM_S_Hotte]

As long as I know, it's not fixed.
Workaround proposed by Autodesk: Use the 2024 version!

[luke.coxonUB8Z4]

Hi There

This problem started for me, soon after I updated from 2025 to 2025.1  

Has anyone heard of any updates from Autodesk on this? 

I compared all the .lin files from previous P3D versions and copied anything missing to my 2025 support folders, but this didn't make any difference.

It also doesn't explain why the LineType property simply disappears.

If a property can disappear from a SLINE and be reinstated with the MATCHPROP command, without affecting any existing P3D data. Then there must be a setting or file that controls this visibility. 

Does anyone know where this control might be?  

Cheers

[dmerrittHQE4L]

I have not heard back from AutoDesk besides their internal group was going to add it to the things to fix in future updates. We as a company reverted back to using '23 until this is resolved or wait for '26 to try it again.

[h_eger]

@dmerrittHQE4L ,

good idea there is no official list of bug fixes in the P3D 2026 yet

[luke.coxonUB8Z4]

Hi all

When I run the Audit project command as per this proposed solution...

https://www.autodesk.com/support/technical/article/caas/sfdcarticles/sfdcarticles/The-sline-linetype...

The Linetype property is reinstated in my properties window. BUT, all my lines are set to ByLayer instead of Continuous, as per other users.

This doesn't solve my problem because in my Project settings I have all my Signal Lines on the same layer. 

Also note that this is the second time I have run the audit in the same project and the problem repeated. This means the above "solution"...

a) Only reinstates the LineType back into the properties window.

b) Does not reinstate the previous line types.

c) Is not permanent. As in, if you go through the pain of reallocating your linetypes, the problem can happen again at any moment.      

Cheers

Luke