Creating a legend slows ArcGIS Pro

[StuartHarvey]

We are experiencing a problem with ArcGIS Pro (2.8 but also with 2.7) in which adding a legend to a layout will cause the entire project to run extremely slowly. This seems to be exasperated by using the 'Only show features in the map extent' option but not exclusively which is making troubleshooting tricky.

Our data is predominately coming from an SDE, the rest being a random assortment of file GDB and shapefiles.

Clearing the caches and setting the display settings to their lowest doesn't help. 

Any ideas or settings to try??

[DuncanHornby]

What's the spec of your computer? ArcPro really needs to be running on a modern computer with a decent graphic card and fast data access.

[StuartHarvey]

The specs are good and ArcPro runs just fine the rest of the time. It is only after adding the legend that it slows to a crawl. 

Processor Intel(R) Core(TM) i9-9900KF

RAM 32.0 GB

Graphics NVIDIA GeForce RTX 2060 SUPER

[MariusHelsem]

Hi, @StuartHarvey!

I'm experiencing the same issue with a PRO project I'm working on. When turning on a legend element for a layer showing a contour dataset ArcPro freezes. Showing/hiding the layer in layout and map view works completely fine, as long as the legend element remains unchecked. 

Did you find any answers or solutions to your problem?

[StuartHarvey]

@MariusHelsem I came up with a couple of workarounds.

1. Make a legend with just the one or two layers that were causing the issue (in my case a road network and contours). Then convert this to a graphic that I could place below a dynamic legend which contained all of the other layers. 

2. Create a proxy feature layer from the contour layer (with only 2-3 features in the layer), symbolise this proxy layer to match the actual contour layer. Then use the proxy layer in the legend instead of the actual contour layer.

I hope either of these are some help to you.

[MariusHelsem]

@StuartHarvey that's great help, thank you
I have used the proxy workaround for now. I also found that, in my case, the contour-symbology was set to unique values (different intervals), but changing to single value made drawing near instant. 
So my takeaway is that PRO hates the combination of big datasets, unique value symbology, and legend.
I will post here if I find a solution/workaround that let's me keep unique values symbology!