Indesign not responding after export PDF - it freezes for a long time

Have you found any fixes? I have this issue too but on files with way fewer pages. For me it just hangs and never finishes. I have to force quit, get rid of the temp file and the PDF it was trying to create as it's just an empty shell. Then I have to export the PDF to a different folder altogether to get it to work. Not 100% sure what's causing it but I have my suspicions that it might be related to that export to Adobe express dialog box that pops up every time I make my PDFs.

Hello - I'd start by exporting half the pages, 50% to see if it hangs on each side or just 1 side. 

If it's only hanging on 1 side then keep halving your document output until you find the culprit page(s) 

If it hangs page 1-50 out of 100 try exporting 1-25 the 26-50 for example - see if it's any faster or still getting the lag.

You might track something down

Could you also try doing File>Package and package the file to another folder locally on your SSD.

Here's some other ideas

Clear InDesign's Recovery Data & Cache

Close InDesign

Go to similar to this: C:\Users\[YourUsername]\AppData\Local\Adobe\InDesign\Version 20.0\en_US\Caches

Delete everything inside the Caches folder

Restart InDesign and try again

As a Test create a new PDF preset to test with

Adjust the PDF Export Settings
Try using PDF/X-4 instead of High-Quality Print.

Disable Optimise for Fast Web View in the export settings

If using Acrobat Layers, turn that off

Reduce Downsampling settings (change images to 225 ppi (should be fine for most commercial printing - you can increase this to higher later on to see if it's causing issues for now set it a bit lower maybe).

If using Transparency Flattening, set it to Medium or High

Disable Background Export
Instead of exporting in the background, try disabling it:

https://creativepro.com/a-new-workaround-for-that-pesky-background-export-issue/

Try resetting your preferences:
Windows: Start InDesign, and then press Shift+Ctrl+Alt. Click Yes when asked if you want to delete preference files.
macOS: While pressing Shift+Option+Command+Control, start InDesign. Click Yes when asked if you want to delete preference files.
A dialog will appear asking to delete the InDesign Preferences, select 'Yes' on this dialog.
Further info and instructions here if needed:
https://helpx.adobe.com/in/indesign/kb/indesign-preferences-support-file-locations.html

What platform, OS and InDesign versions? 

Do your files are stored locally - or on a server / cloud? 

Hardware configuration? 

Unfortunately, we are not mind readers...