Desktop Client: Simulation Error: Simulation has stopped abnormally with transactions still in the system

This article applies to iGrafx Process and iGrafx Process for Six Sigma Client tools

If you receive an error during simulation of "Simulation has stopped abnormally with transactions still in the system" there can be various reasons for this. The error may in fact give some guesses as to why this has occurred; specifically:

1. The simulation clock has run to its limit.
2. Transactions are locked in resource queues because the resource acquisitions can never occur.
3. Transactions are blocked by an input condition and can never leave the input queue.

It's possible there are other errors or output messages that might also be given in addition to this message, and they will likely hint at the source of the problem.

Some possible reasons for the message (this is not an exhaustive list):

Inputs: You have an input queue constraint that can never be satisfied / completed (e.g. you also get a message of "Transactions are blocked by an input condition and can never leave the input queue"). For example:
1. If you batch together 10 transactions, but you've setup a 'Completion' type generator that will only put 1 transaction at a time into the process (this generator condition is the default), then there would not be 10 transactions to batch, and the one transaction will be stuck.
2. If you batch transactions, and don't 'unbatch' at some point, and then perform a batch again, you are 'batching' the already-batched transactions, and you again may not be generating enough transactions to satisfy your batch condition(s).
Resources: You have transactions that are waiting to acquire a resource, and that resource cannot ever be acquired by the transaction. This can be due to various reasons; for example:
1. Use of the 'Wait' switch (which causes resources to wait with the transaction when not all resources have been acquired yet)
2. Not having enough resources in a pool to satisfy your constraint (e.g. you have 1 resource allocated to a Swimlane, and you've put the constraint that you need 2 of that type of resource per transaction on the Resources page of the step where the transaction is stuck).
3. Transactions wait for resources that never become available (e.g. a schedule issue, or because they are blocked from being released by another transaction).
Simulation clock has run to its limit. There is a separate KB article for this potential cause and solutions; please see that article.

We recommend that you look for the conditions above. It may help to run the simulation in Trace mode to look for where transactions are 'blocked' (goes red) from proceeding for longer than you expect them to be, or for other places where a step is waiting on resources (goes yellow) where you didn't expect it to.