Updated 27 September 2026
Open the XER in five steps
- Get the P6 project export. Ask the planner for a Primavera PM (XER) project export. In P6 Professional, the export starts under File → Export; choose Primavera PM (XER), select the project, then save the file. Keep the original export for comparison.
- Download the file to your Mac. Save the .xer file to a local folder. If Finder shows a cloud placeholder, download it first; an offline viewer cannot open bytes that are still only in the cloud.
- Open it in GanttPeek. Install GanttPeek on an Apple silicon Mac running macOS 14 or later. Open the local export from the app or Finder. The parser checks the file content rather than trusting only its extension.
- Inspect the schedule and its warning. Review the project and WBS outline, activities, dates, durations, progress, supported constraints, relationships, resources and assignments. Read the in-app partial-import warning before using the view for a decision.
- Export a readable copy if needed. Use File → Export Schedule Report as PDF for a report, Export Tasks as CSV for a table, or Export Gantt Chart as PDF or PNG for the timeline. These are new files; the source XER stays untouched.
What you can check in an XER schedule
An XER export can hold more than one project. GanttPeek reads the project records and presents their WBS nodes as summary rows, with activities beneath the relevant node. That lets you follow the shape of a programme instead of reading a flat list. The task view and Gantt timeline are for reviewing the extracted schedule, not for planning or recalculating it.
For activities, the parser reads names, available start and finish dates, planned duration, progress, milestone status and recognized constraint types. It reads supported predecessor relationships, including finish-to-start, start-to-start, finish-to-finish and start-to-finish links, with lag where present. Resource identities and basic assignments are carried across. The app shows fields as unavailable when the export does not provide them; an empty field should not be treated as zero or as proof that the planner left it blank.
Use the PDF report when someone needs a readable schedule without the app, the CSV when they need extracted task rows, and the chart export when they need the visual timeline. The output represents the data GanttPeek read. For a contractual review, forensic audit or formal progress claim, check the original in P6 with the schedule owner. A viewer’s report is not a certified reproduction of the P6 layout or its scheduling engine.
Free ways to inspect an XER file
If you already have authorized access to Primavera P6, opening the export there is the most complete route: P6 can work with its own planning data and is the right place to verify or change the schedule. Ask the sender for a PDF or spreadsheet export when you only need to read a few dates and do not need to navigate the XER itself. A PDF is easy to share, but it cannot reveal fields the sender omitted.
GanttPeek includes one real project at no charge, and reopening that project does not use another slot. Its built-in sample lets you explore the interface before selecting a work file. Unlimited projects require GanttPeek Pro. Some web viewers or converters offer free access, but first check whether they require an upload and whether your organization permits sharing the schedule with that service. The local GanttPeek path does not send the selected file to a conversion server.
What it cannot do
GanttPeek is read-only. It cannot edit activities, reschedule dates, level resources or write an XER file. It does not read P6 calendars, costs, activity codes, notes or steps. It does not reconstruct the entire Primavera project or guarantee the same calculations and display as P6. The app presents a partial-import warning so these omissions are visible while you inspect the file.
On Mac, a selected file can be up to 100 MB. macOS 14 Sonoma or later and Apple silicon are required. If an export is damaged, has no project record, or is not a Primavera XER export, ask the sender for a fresh project export. Renaming an unrelated file to .xer will not make it readable. Keep a copy of the source and compare important dates and relationships with the schedule owner before relying on an extract.
Questions about XER files on Mac
Can macOS open an XER file by itself?
An XER project export needs an application that understands Primavera data. GanttPeek reads supported XER exports locally on Apple silicon Macs with macOS 14 or later.
Can I open an XER file for free on Mac?
GanttPeek includes one real project at no charge and a built-in sample. Reopening the same project does not consume another slot. Unlimited projects require Pro.
Does an XER file have to be uploaded?
No. GanttPeek parses the selected export on your Mac and works offline once the file is downloaded locally. It requires no account.
Will I see calendars, costs or activity codes?
No. The XER parser reads projects, WBS, activities, dates, durations, progress, supported constraints, relationships, resources and assignments. Calendars, costs, activity codes, notes and steps are not read.
Can I edit the XER and save it back?
No. GanttPeek is a read-only viewer and does not write XER files. Use Primavera P6 or another suitable planning tool to change a schedule.
Can I export the XER as PDF or CSV?
Yes. GanttPeek can create a PDF schedule report, task CSV, and Gantt chart PDF or PNG from the fields it extracts. The original XER is not modified.