Troubleshooting & FAQ

Symptoms first, then the fix. If your problem isn't here, get in touch.

The chart doesn't render

The landing page is still showing

The visual needs all three of Project hierarchy, Start date and End date before it draws anything. Check the Build pane — an empty well is the answer nine times out of ten. Every other field is optional and never gates rendering.

The task list is there, but the timeline is empty

Rows with no bars mean the visual received the tasks but couldn't read their dates. In order of likelihood:

• The dates are text. Change both columns to a Date or Date/Time type in Power Query or the model view, then re-bind them.
• One of the two dates is blank. A task needs both a start and an end to be drawn — see A task has a row but no bar.
• The bars are off-screen. At a fixed zoom the timeline can be far wider than the visual. Click Auto Fit in the top bar, or set Format → Zoom and scroll → Default zoom preset to Automatic.

The chart area is blank

Every field is bound, but nothing is drawn — no rows, no bars:

• A filter or slicer has emptied the data. Check the visual's filter card and the page-level filters.
• The hierarchy columns and the date columns aren't related. If they come from different tables with no relationship between them, Power BI has nothing to return. Drop the same fields into a table visual to confirm you get rows.

Bars and dates

A task has a row but no bar

The row's start or end date is missing, or isn't a value the visual can read as a date. The task stays in the list — so the hierarchy is still complete — but there is nothing to position on the timeline. Fix the date at the source; for genuinely open-ended tasks, supply a provisional end date (today, or the project's end) in a calculated column.

All the bars are bunched up around 1970

A date well is being counted instead of read. Select the dropdown arrow on the field in the Start date or End date well and choose Earliest (for start) or Latest (for end) rather than Count. A count of 1 read as a date lands at the very beginning of 1970.

Days and months are swapped

Your dates are text, and text like 05/01/2026 is ambiguous — it may be read as 1 May rather than 5 January. Convert the columns to a real Date type, using Change type → Using locale in Power Query if the source is day-first. Once the model holds true dates, there is nothing left to misread.

A bar is a thin sliver

Two causes, and they look the same:

Cause	How to tell	Fix
The end date is before the start date	The tooltip shows a negative duration	Correct the dates at the source
The task is very short for the zoom level	It looks normal at Day or Week zoom	Zoom in, or turn on Show task labels so short tasks stay identifiable

Bars are never drawn narrower than 2 px, so a short task can't vanish entirely.

A task is drawn as a diamond instead of a bar

Its start and end dates are the same, and Zero-duration tasks as milestones is on (the default). Turn it off under Format → Milestones → Options to get a short bar back, or change the shape with Task milestone symbol. See Zero-duration tasks.

If the task really lasts a day, check that the end date isn't being truncated — a task from 09:00 to 17:00 on a Date/Time column is a bar; the same task on a Date-only column is a milestone.

Two tasks merged into one row

The Project hierarchy path is what identifies a task. Two rows with the same name under the same parent — two Testing tasks in one project, say — are one task as far as Power BI is concerned, and arrive as a single row. Make the names unique (Testing — round 1), or add a level to the hierarchy that separates them, such as a phase or a task ID column.

A row is called "(Blank)"

A hierarchy column is empty for that row. It's common with ragged hierarchies, where some tasks have a sub-task level and others don't. Either fill the gap at the source — repeating the task name at the lower level works — or filter blanks out in the visual's filter card.

A project bar is longer than I expected

A parent's bar isn't read from your data: it spans the earliest start to the latest end of everything beneath it, including tasks you may have collapsed out of sight. One child with a wrong year stretches the whole project. Expand the project and sort by End date, descending, to find it quickly.

Tasks are in the wrong order

Format → Sort by orders tasks within each level of the hierarchy, by Start date unless you change it. To follow your own sequence, choose Data order and set Sort by column on the model column (Task sorted by Task Number). Direction has no effect with Data order. See Sorting tasks.

Progress

45% shows as 0% — or everything shows as 100%

The progress scale is being read the wrong way round: 0.45 treated as 0.45 out of 100, or 45 treated as 45 out of 1 and capped. Auto gets it right when the measure carries a percentage format or is a whole number; an unformatted decimal measure is the case it can misjudge, especially when a filter leaves only values of 1 or less.

Set Format → Progress → Progress scale to 0–1 or 0–100 explicitly — or, better, apply a percentage format to the measure. See Progress scale.

A project's percentage doesn't match my own figure

A parent's progress is the simple average of its direct children: every child counts equally, whatever its duration or effort, and a child with no progress value counts as 0%. If your organisation reports weighted progress, show that measure in an Extra column next to the project instead.

Actual and planned progress disagree wildly

Both measures are read on the same scale. If one is a fraction (0.45) and the other a percentage (45), one of them will be wrong whichever scale you pick. Convert one in DAX so they match.

There's no checkmark on a finished task

The green checkmark needs three things: a field in Progress (%), a value of 100% or more for that task, and Format → Project hierarchy → Show completion checkmarks on. A task at 99.6% is not complete — round the measure if that's what your data holds.

Top-level project rows never show a checkmark, and checkmarks are hidden in high-contrast mode.

The percentage isn't shown next to the bar

Format → Data labels → Show progress percentage must be on, and Progress (%) must be bound. Zero-duration tasks drawn as milestones show their progress differently: the marker is outlined while in progress and filled when complete.

Dependencies

No arrows appear at all

• Both Task ID and Predecessor ID must be bound. One without the other draws nothing.
• Format → Dependency lines → Show must be on.
• The values in Predecessor ID must be Task IDs, not task names.

Some arrows are missing

An arrow that can't be resolved is skipped silently — there is no error. Check, in this order:

Cause	Example	Fix
The predecessor ID doesn't match any Task ID	7 when the task is 007, or A-7 vs A7	Make the values match exactly, character for character
The predecessor is filtered out	A slicer hides the phase it belongs to	Nothing to fix — the arrow returns with the task
Duplicate Task IDs	Two tasks both numbered 12	Arrows go to the first one only; make IDs unique
Either task has no dates	A predecessor with a blank end date	Supply the date
The wrong separator	3 4 or 3/4	Separate multiple IDs with a comma or a semicolon
A task lists itself	Task 5 with predecessor 5	Remove it

Arrows ignore my lag and link types

By design. Values like 3FS+2d or 4SS are accepted so you can paste a Microsoft Project export unchanged, but the link type and lag are dropped: every arrow runs from the end of the predecessor to the start of the successor. Bars are positioned by your dates alone — the visual doesn't reschedule anything.

An arrow points backwards

The successor starts before its predecessor ends in your data. The visual draws what it's given, and a backwards arrow is usually worth knowing about: it's either a schedule conflict or a start-to-start link recorded as a plain ID.

Milestones and links

Milestone markers are missing

• Hide markers outside bars is on, and the milestone date falls before the task's start or after its end. Turn it off under Format → Milestones → Options.
• The milestone column is text or blank for that task. It must be a date type.
• The marker is there but tiny — raise Marker size (%), which is relative to the task bar height.

A task has no link icon

• The address doesn't start with http:// or https://. Relative paths, file: paths, mailto: links and addresses with leading spaces are all ignored.
• The address is longer than 2,048 characters.
• The row is a project or summary row. Links are shown on the lowest-level tasks only.

See URLs.

The link menu says "URL1" and "URL2"

Menu entries are labelled with the column names as they appear in the well. Rename the fields — in the model, or by double-clicking them in the URLs well — to something like Ticket and Specification.

Colours and legend

The legend doesn't appear

The legend is drawn only when a field is bound to Legend and Format → Legend → Show is on. Without a Legend field every bar takes the Default color, and there is nothing to describe.

A project bar is a different colour from its tasks

A parent inherits a legend colour only when everything beneath it shares that colour. Mixed children — two phases on track, one late — give the parent the Default color instead. Choose a neutral default under Format → Data colors so it reads as "mixed" rather than as a category of its own.

My colour choices have no effect

• High contrast mode is on, so Power BI supplies every colour. Your settings return when it's switched off.
• The legend value you coloured is no longer in the data — filtered out, or renamed in the model. A renamed value is a new value and takes the next theme colour.

Dark mode did nothing

Dark mode restyles the chart's shell — backgrounds, text, grid lines — not your bar colours, and it is ignored in high-contrast mode. If the visual sits on a dark report page and still has a white background, check Format → General → Effects → Background as well: that's Power BI's container, drawn behind the visual.

Navigation and interaction

The zoom controls have disappeared

Format → Appearance → Header → Show top bar is off. The top bar carries both the search box and the zoom controls, so hiding it removes both; viewers are left at your Default zoom preset, though they can still zoom with Ctrl + wheel, a trackpad pinch or the date header. To hide only the search box, use Show search bar instead.

The chart opens at the wrong place

Format → Zoom and scroll → Default scroll position is Start by default. Set it to Today for live projects. With Automatic the whole schedule fits the visual's width, so there is nothing to scroll — pick a fixed zoom preset for the scroll position to matter.

The Today line isn't visible

• Format → Today line → Show is off.
• Today falls outside your schedule's date range — a finished project, or a plan that hasn't started — so the line isn't on the timeline.
• It's there, but scrolled out of view. Set Default scroll position to Today.

My column width keeps resetting

A width set while editing is saved with the report. A width dragged by a viewer in reading view lasts for their session only, and returns to yours on refresh. Set the width you want everyone to get in edit mode — by dragging, or with Format → Project hierarchy → Column width (200–600 px).

Search hides rows but other visuals don't change

Search is a viewing aid inside the visual: it narrows the task list to matching tasks and their parents, and nothing else on the page reacts. To filter the page, click a task or a legend entry, or use a slicer.

Clicking a task doesn't filter anything

• Edit interactions has been set to None between this visual and the others.
• The other visuals aren't built on fields related to your hierarchy columns in the model.
• The visual is in a context where Power BI turns interactions off — the chart becomes static there, and selection, collapsing and resizing are all disabled.

Clicking another visual removes tasks instead of dimming them

Expected. The Gantt Chart is filtered by other visuals' selections rather than highlighted, so a click on a bar chart leaves only the matching tasks — and projects' summary bars shrink to span just those tasks. To stop a particular visual affecting the Gantt, use Format ribbon → Edit interactions and set it to None.

Expanded and collapsed projects reset for viewers

Viewers can expand and collapse freely, but only an editor's state is saved with the report. Set the opening state in edit mode and save; for several preset views, capture each one as a bookmark. See Expand & collapse.

Large datasets

"Loading tasks… N rows so far"

Not an error. Large datasets arrive in segments of 30,000 rows, and the notice shows the running count until the last one lands.

"Showing the first N rows — the dataset is too large to load completely"

You've passed the visual's 90,000-row ceiling. The chart is accurate for the rows it has, but it isn't the whole schedule. Filter to a programme, a date range or open tasks only — or remove the lowest hierarchy level so Power BI sends one row per task group rather than per sub-task. See How much data the visual can show.

If even the first segment can't be used, the notice reads "The dataset is too large to load" and the fix is the same.

"Showing the first N rows — Power BI couldn't load the remaining data"

Power BI stopped delivering data part-way — typically a memory limit on a very wide dataset, or a dropped connection. Refresh the visual; if it persists, reduce the number of columns in Tooltip and Extra columns, or filter the data. With no rows at all, the notice reads "Power BI couldn't load the data".

"Something went wrong while displaying the data"

The data arrived but couldn't be drawn. Refresh first. If it comes back, remove the optional fields one at a time to find the column involved, and send us a few sample rows — this one is ours to fix.

The chart is slow to scroll or zoom

Tens of thousands of bars are slow to read as well as to draw. Collapse to the project level before saving, filter to the active date range, and prefer Month or Quarter zoom over Day for multi-year schedules.

Licensing

A license notification appears on the visual

The visual is unlicensed in that environment. Every feature keeps working; the notification is what a license removes. See Licensing.

The notification appears even though we bought a license

• Licenses are per user. Everyone who edits or views the report needs one assigned.
• Licenses are cached for a Power BI session. A newly-licensed user should sign out and back in.
• The environment may not support AppSource licensing — Report Server, Embedded, Publish to web, SharePoint and sovereign clouds all need a direct license key instead.

My license key says "License verification requires HTTPS"

Key verification uses browser cryptography that only runs on secure origins. Enable HTTPS on your Power BI Report Server and reload the report. The other status messages are explained in What the status line tells you.

Getting more help

• In-product: the Documentation button on the visual's landing page opens this site.
• Email support: hello@chartpad.io

Include your Power BI version (Desktop or Service), the visual version, a screenshot, and a small sample of your data — three or four task rows with their dates, in the shape described in Getting started, is usually enough to reproduce a problem.