BC Symptom → Root Cause Catalogue

BC-specific symptoms mapped to their most likely root causes. Use this during Step 1 triage to narrow hypotheses before reading code.

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1. Wrong value shown on page

1.1 FlowField shows 0 or stale value

Root causes by probability:

#	Root cause	Probability	Signal
1	CalcFields not called in code path	HIGH	Value correct in table, wrong on page in code context
2	SetLoadFields excludes the FlowField	HIGH	Other fields load fine, only this one is 0
3	CalcFormula filter references wrong field	MEDIUM	Value is a number but wrong amount
4	Missing SumIndexFields key for CalcFormula	LOW	Correct on small datasets, wrong on large ones
5	Circular FlowField dependency (AL0896)	LOW	Compiler warning present

Quick check: Does the field show the right value in the BC UI but wrong in code? → CalcFields missing.

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1.2 Regular field shows wrong value

Root causes by probability:

#	Root cause	Probability	Signal
1	SetLoadFields truncating the field list	HIGH	Other fields on the same record also suspicious
2	xRec used instead of Rec in trigger	HIGH	Value correct on first open, wrong after edit
3	Wrong filter applied before Get/Find	MEDIUM	Different records show same wrong value
4	Field modified in event subscriber without intent	MEDIUM	Value was correct before an extension was installed
5	Data migration ran with wrong values	LOW	All existing records wrong, new records correct

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1.3 Decimal shows 0 after calculation

Root causes by probability:

#	Root cause	Probability	Signal
1	Integer division — both operands are Integer type	HIGH	Formula looks right but result is always 0 or truncated
2	Round function rounding to 0	MEDIUM	Small values always 0, large values correct
3	Field not validated — Validate not called	MEDIUM	Related fields not updated after assignment

Quick check: Cast one operand to Decimal explicitly: Result := Rec.Qty * 1.0 / Rec.Total.

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2. Record not found

2.1 Get returns false unexpectedly

Root causes by probability:

#	Root cause	Probability	Signal
1	Wrong company context	HIGH	Works in one company, fails in another
2	Key fields in wrong order or incomplete	HIGH	Only some records fail
3	SetRange filter active before Get	MEDIUM	Get ignores filters — but a preceding SetRange on a global variable persists
4	Record deleted by concurrent process	LOW	Intermittent failure
5	Permission — no Read on table	LOW	Error is actually a permission error surfaced as not found

Quick check: Get ignores filters. If you set SetRange on a record variable and then call Get, the filter is irrelevant to Get but may affect subsequent FindSet. Check if the variable is reused.

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2.2 FindSet / FindFirst returns empty

Root causes by probability:

#	Root cause	Probability	Signal
1	Filter too restrictive — wrong field or value	HIGH	Removing one filter makes it work
2	SetRange on a Date field with wrong format	HIGH	Date comparison fails silently
3	Wrong SecurityFilter scope	MEDIUM	Works for admin, fails for regular user
4	DataPerCompany = false table accessed with company filter	LOW	Tenant-wide table filtered by company
5	TableRelation filter applied implicitly	LOW	Related record exists but filtered out

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3. Action / trigger not executing

3.1 Event subscriber not firing

Root causes by probability:

#	Root cause	Probability	Signal
1	Signature mismatch — parameter name, type, or order wrong	HIGH	No compile error but subscriber never called
2	Wrong ObjectType or ObjectId in attribute	HIGH	Easy to get wrong on table vs codeunit
3	IsHandled = true set by a prior subscriber	MEDIUM	Other subscribers for same event DO fire
4	SkipOnMissingLicense skipping silently	MEDIUM	Works in some user contexts, not others
5	Extension not published / not active	LOW	Check extension list

Quick check: The subscriber attribute [EventSubscriber(ObjectType::Table, Database::"Customer", 'OnAfterInsert', '', false, false)] — the ObjectId must be the exact table/codeunit, the event name must be spelled exactly, including case.

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3.2 OnValidate trigger not firing

Root causes by probability:

#	Root cause	Probability	Signal
1	Field assigned directly (Rec.Field := value) instead of Rec.Validate(Field, value)	HIGH	Value changes but related fields don't update
2	IsHandled set to true in another subscriber	MEDIUM	Trigger fires for some users, not others
3	Trigger in tableextension but base table trigger runs first and errors	MEDIUM	Error before tableextension trigger executes

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3.3 Action on page does nothing

Root causes by probability:

#	Root cause	Probability	Signal
1	Enabled expression evaluates to false	HIGH	Action visible but greyed out or click has no effect
2	Visible expression hides it but layout glitch shows it	MEDIUM	Inconsistent across records
3	Missing permission on codeunit called by action	MEDIUM	Works for admin, fails silently for users
4	CurrPage.Update() not called after action — UI not refreshed	LOW	Action runs but page looks unchanged

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4. Posting failures

4.1 Error during posting — unexpected validation

Root causes by probability:

#	Root cause	Probability	Signal
1	Event subscriber in OnBefore posting event errors	HIGH	Error message mentions an unexpected codeunit
2	Missing mandatory field added by extension	HIGH	Error mentions a field that is custom
3	TestField on a field not populated by the posting flow	MEDIUM	Field exists but was never required before
4	G/L account or posting group missing	MEDIUM	Configuration error, not code
5	Commit inside event subscriber conflicting with posting transaction	LOW	Intermittent, only under load

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4.2 Posting succeeds but ledger entry wrong

Root causes by probability:

#	Root cause	Probability	Signal
1	Amount calculation error before posting codeunit	HIGH	Amount visible on document before posting is already wrong
2	Event subscriber modifies amount in OnBefore posting	MEDIUM	Amount correct before subscriber fires, wrong after
3	Wrong G/L account resolved from posting group	MEDIUM	Posted to wrong account, right amount
4	Rounding difference not handled	LOW	Off by 1 cent on large amounts

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5. Permission errors

5.1 "You do not have permission to read table X"

Root causes by probability:

#	Root cause	Probability	Signal
1	Missing permission set entry for custom table	HIGH	New table added, permission set not updated
2	Indirect permission not declared on codeunit	MEDIUM	Codeunit accesses table on behalf of user, no Permissions property
3	Wrong InherentPermissions on codeunit	MEDIUM	InherentPermissions = X without data permissions
4	User assigned wrong permission set	LOW	Works in SaaS for admin, fails for real user

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6. Performance symptoms

6.1 Page loads slowly

Root causes by probability:

#	Root cause	Probability	Signal
1	FlowField CalcFields called inside repeat...until loop	HIGH	Performance degrades linearly with record count
2	Missing SetLoadFields — all fields loaded	HIGH	Network/DB time high, all field values available
3	Too many FlowFields on list page (>4)	MEDIUM	Each FlowField fires a query per visible row
4	OnAfterGetRecord trigger doing expensive operations	MEDIUM	Same slow pattern on every record
5	Missing index for filter field	LOW	Filter on unindexed field causes full table scan

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7. Data integrity issues

7.1 Duplicate records

Root causes by probability:

#	Root cause	Probability	Signal
1	Number series allows manual entry AND auto-entry	HIGH	Duplicates only when number entered manually
2	Insert called without checking existence	HIGH	Batch process creates duplicates on re-run
3	Race condition — two sessions insert same key simultaneously	LOW	Intermittent, only under load

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7.2 Orphan records after delete

Root causes by probability:

#	Root cause	Probability	Signal
1	Missing OnBeforeDelete cleanup in tableextension	HIGH	Related custom records persist after parent deleted
2	DeleteAll used instead of Delete(true) — triggers don't fire	HIGH	Works with single delete, fails with bulk delete
3	Missing CalcFields/CalcSums reset on related table	LOW	Aggregation wrong after delete