While exporting application, I got following error : processModel 686

Before exporting first check for the missing dependencies in the General Tab. There you will get the list of all dependent rules/processes for the ones u have included in the application. Just add them and it shud be fine.

Just to follow the best practice, crate two different applications to export.
1. Which contains only the CDT's and data stores which are used.
2. Which contains the rest of the rules/processes etc.

While importing it to the other server, first import the Datastore one, make sure it is mapped to the entity's and then import the second application.
This helps reducing most of the issues with references to the DS.

On checking Missing dependencies no dependencies are shown.

Check if you have used any rules in the process model and those are included in your application.

I have added all the rules required for the application. No rules are showing in missing dependencies. Still am getting inavlid reference error. How to find the missing rule i.e invalid reference rather than checking it manually as it is timeconsuming process.

I would suggest you to check the deletion log available under <APPIAN_HOME>/logs. This will help you find the rule this ID belongs to.

Please refer to the following link : forum.appian.com/.../b-55599

I would suggest downlaod Jar file from
forum.appian.com/.../apps Content Details by UUID.
In this there is function which tell Content name or Process model Name by UUID. Whatever the content missed on import check its by using function and then include in export application.

As u decribed above , i think in your rule there is some document or image file or link to other content which is not include in the application.
One more thing Check Missing dependency will never mention all the reference.