Dissolve error in Model Builder ArcGIS 10.1

[MatthiasMohaupt]

Hello,
I´m trying to do a simple dissolve task in Model Builder 10.1 which worked fine in ArcGIS 10. It also works as desired when I use the tool outside the Model Builder. Strangely, besides the fact that the number of features is falsely increasing after running dissolve, the output is singlepart although I checked the multipart option and the input is a multipart feature class.
Any suggestions?
Thanks!

[KenHartling]

I'm unable to reproduce the problem.  Please double check to make sure you are using the exact same parameters when running dissolve inside and outside of model builder.
If you are confident that you are, please contact support to see if they are able to figure out what is going on. 
Thanks,
Ken
Senior GP Product Engineer

[BenPlunkett]

I am having the same trouble with the dissolve tool in 10.1 not creating multipart polygons.  I have three separate polygons that I want to dissolve into one multipart feature.  The only way that I can get the dissolve tool to operate correctly is when using the Dissolve tool outside of model builder while not in an edit session. 

The dissolve tool will not create multipart polygons in model builder whether I am in an edit session or not.  It also fails to create multipart polygons when using the dissolve tool outside of model builder when I am in an edit session.

My colleagues are experiencing the problem.  We all upgraded to 10.1 this week and are now experiencing this problem for the first time.

[DanielHofer]

Same problem here.

[KristenE]

Has this issue been resolved? It looks like this person had the same issue- http://forums.arcgis.com/threads/69378-ArcGIS-10.1-Dissolve-multipart-features-not-working. I have 3 people in my office and we are all having the same problem. All working on Windows 7 (not Windows XP) 32-bit machines. Dissolve tool worked fine in 10.0 and after the upgrade it does not dissolve multipart features.

[MicheleH_DNReply]

Hi there,  just asking the same question as the last person really - does anyone know if ESRI is working on this.  I have the exact same problem and have done since moving to 10.1.  Dissolve won't create a multi-part poly in model builder.  I have to run my model up to the dissolve then manually go into the feature class and merge the polygons together then complete my model.  Quite a pain.

I am running Windows 7, 10.1 sp 1, 32 bit as well.  Be good to know if this will be fixed in the next release which I believe is in a couple of weeks?

[MelanieSummers]

Hello,

I also was not able to reproduce the issue when running only the dissolve tool in ModelBuilder, if possible, could you please share your model, I'd like to see if there is a common element preventing the dissolve tool from creating multipart polygons.

Thanks,
Melanie S.

[BenPlunkett]

Okay, so I did some testing to try and figure out why and when this error is occurring.

I actually had some trouble getting the error to happen again.  The models I have been testing only have the dissolve process without any dissolve field selected.  I have found that the error only occurs when attempting to make multi-part features.  The model will function as if the "Create multipart features" option is not selected.  The result will dissolve all overlapping polygons, but each will be an individual feature instead of a singular multipart feature.

[ATTACH=CONFIG]23261[/ATTACH]


I tried the simple process in modelbuilder and a python script, attempting multipart and single feature outputs.  The error occurred in both modelbuilder and python multipart outputs.  However, the error only occurred when I had either several browser windows open (Chrome) or had any streaming video or audio at the time.  I tried to run the dissolve outside of the model during similar browsing activity, and it worked perfectly.  It even worked when I opened up 8 videos simultaneously.

I'm running Arc Desktop 10.2 SP1 on a Windows 7 - 32 bit, 4 GB RAM, Core 2 Duo E8400 3.0  GHz processor, which exceeds ESRI system requirements.

I hope this can help you at least duplicate the error I am having.  Thanks for any help or information you can give me about the situation.

-Ben

[nancyvonmeyer]

I am not able to get the dissolve geoprocessing to work in 10.1 and it worked just fine in 10.0, this is a fairly simple dissolve and not a large data set.

[MicheleH_DNReply]

Ok - so I didn't subscribe to this thread so I didn't see that I was asked to post my model...  sorry!!

I am still having this issue though so here is my model (I hope - not quite sure how to do this...)  The dissolve that isn't working is in in the middle of the model after 'Layer - 19'

It sum's all the attributes correctly and it dissolves where block are adjacent - it just doesn't make multi-part polys where the blocks are not adjacent.