Disclaimer
Any changes to Microsoft Defender configuration, or to antivirus software in general, should always be discussed with and approved by your local IT department.
The measurements presented in this article are based on a single, dedicated project. Performance impact may vary depending on project size, structure, system configuration, and installed software.
Introduction
This article summarizes test results evaluating the impact of Microsoft Defender real-time scanning on Automation Studio (AS) rebuild and project transfer times. The goal was to quantify performance differences when the project directory is scanned versus excluded from scanning.
Test Setup and Methodology
The tests were performed on a real project. The following methodology was used to ensure repeatable results:
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Five rebuild attempts per scenario.
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After each rebuild, the project was uploaded to AR Sim.
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The first rebuild after starting Automation Studio was excluded from evaluation due to initial warm-up effects.
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The
-profileoption was enabled during rebuild to measure timing. -
Only one Automation Studio instance was running.
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Background applications running on Windows:
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Outlook
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Microsoft Teams
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Excel
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Average CPU load at rebuild start: approximately 25%.
Two Automation Studio versions were tested:
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Automation Studio 4.12
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Automation Studio 6
Two scenarios were compared:
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Project located in a standard folder (scanned by Microsoft Defender).
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Project folder added to the Microsoft Defender exclusion list (not scanned).
Project Characteristics
The tested project contained the following components:
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mapp View: 17 pages
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mapp Motion: 9 axes
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Safety configuration
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26 application tasks
Performance Results
Standard Folder (Microsoft Defender Scanning Enabled)
Automation Studio 4.12
| Attempt | Rebuild Time [s] | Time from “Waiting for differences…” to “Transferring transfer module” [s] |
|---|---|---|
| 1 | 86 | 49 |
| 2 | 81 | 42 |
| 3 | 86 | 28 |
| 4 | 82 | 27 |
| 5 | 90 | 48 |
| Average | 85 | 38.8 |
Automation Studio 6
| Attempt | Rebuild Time [s] | Time from “Waiting for differences…” to “Transferring transfer module” [s] |
|---|---|---|
| 1 | 48 | 35 |
| 2 | 48 | 37 |
| 3 | 53 | 45 |
| 4 | 48 | 19 |
| 5 | 46 | 19 |
| Average | 48.6 | 31 |
Folder Excluded from Microsoft Defender Scanning
Automation Studio 4.12
| Attempt | Rebuild Time [s] | Time from “Waiting for differences…” to “Transferring transfer module” [s] |
|---|---|---|
| 1 | 43 | 5 |
| 2 | 44 | 4 |
| 3 | 40 | 4 |
| 4 | 41 | 4 |
| 5 | 41 | 4 |
| Average | 41.8 | 4.2 |
Automation Studio 6
| Attempt | Rebuild Time [s] | Time from “Waiting for differences…” to “Transferring transfer module” [s] |
|---|---|---|
| 1 | 37 | 2 |
| 2 | 36 | 2 |
| 3 | 36 | 1 |
| 4 | 38 | 3 |
| 5 | 38 | 2 |
| Average | 37 | 2 |
Same results placed as a picture for better overview
Relative Improvement
| Metric | AS 4.12 | AS 6 |
|---|---|---|
| Rebuild time reduction | 51% | 24% |
| Transfer preparation time reduction | 89% | 94% |
Analysis
Excluding the project folder from Microsoft Defender scanning resulted in significant performance improvements:
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The time required to generate differences and start the transfer was reduced:
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AS 4.12: approximately 38.8 s → 4.2 s
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AS 6: approximately 31 s → 2 s
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Rebuild times were also notably shorter:
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AS 4.12: 85 s → 41.8 s
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AS 6: 48.6 s → 37 s
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The most pronounced effect was observed during the transfer preparation phase, indicating that file access and comparison operations are strongly impacted by real-time scanning.
Productivity Impact
For Automation Studio 4.12, the combined rebuild and transfer time was reduced by an average of 77 seconds per cycle. Assuming 50 transfers per day over a work week, this corresponds to a time saving of approximately:
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19,250 seconds per week
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~5.3 hours per week
While the measurements focused on full rebuilds, the reduced transfer preparation time also benefits regular project uploads, leading to additional time savings during daily development and commissioning work.
Summary
The tests clearly show that excluding Automation Studio project directories from Microsoft Defender real-time scanning can have a substantial impact on rebuild and transfer performance. The improvement is especially significant for transfer preparation, but compilation times also benefit. For workflows involving frequent rebuilds and downloads, this configuration change can lead to measurable productivity gains.
Thanks colleagues from B&R Poland for this measurements and sharing results with us
