[SalesForce] Process Builder works only when the record is being edited,Initial Creation throws error

Approval Process
We have a process builder which auto approves a quote based on a specific approval process with a criteria defined as discountpercent__c > 2.Wherein the field discountpercent__c is a rollup summary field and sums it up based on discount field in quote.
Now the problem is that the quote gets auto approved only when it is edited.If we try creating a new record it throws the following error

Workflow Action Failed to Trigger Flow The record couldn’t be saved
because it failed to trigger a flow. A flow trigger failed to execute
the flow with version ID 30136000000DWbb. Contact your administrator
for help.

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But manually submitting the record works fine.Any idea on why Process builder causes such error???

Updated Error:

This report lists the elements that the flow interview executed. The
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Flow Details Flow Name: Quote_Approval Type: Workflow Version: 1
Status: Active

Flow Interview Details Interview Label: Quote_Approval-1_Quote Current
User: Baku A (00536000002df2q) Start time: 7/28/2016 2:16 AM Duration:
0 seconds

How the Interview Started Baku A (00536000002df2q) started the flow
interview. Some of this flow's variables were set when the interview
started. myVariable_old = null myVariable_current = 0Q036000000AYlnCAG

ASSIGNMENT: myVariable_waitStartTimeAssignment
{!myVariable_waitStartTimeVariable} Equals {!Flow.CurrentDateTime}
Result {!myVariable_waitStartTimeVariable} = "7/28/2016 2:16 AM"

DECISION: myDecision Executed this outcome: myRule_1 Outcome
conditions: and
1. {!formula_myRule_1} (true) Equals true Logic: All conditions must be true (AND)

SUBMIT FOR APPROVAL: myRule_1_A1 Inputs: objectId =
{!myVariable_current.Id} (0Q036000000AYlnCAG) comment = null
processDefinitionNameOrId = Quote_Approval skipEntryCriteria = false

Error Occurred: No applicable approval process was found.

Best Answer

Since the discountpercent__c is a roll-up summary. At creation your record won't have a value (you can't have children before you insert a record as you need it's Id).

What is happening is that you flow is calling the approval process, but the record does not pass the entry criteria and hence the error you found.

A way to avoid that is to make sure the entry criteria for your flow is the same as the Approval Process.