How to Improve Performance When Processing Large Excel Files in UiPath?

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1

Hi all,
I’m automating a process that involves reading and processing large Excel files (50,000+ rows). The current workflow using Read Range and looping through rows is very slow.

What are some ways to optimize performance when working with big Excel datasets in UiPath?

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2

@SR_9128,

You can try using Workbook Read Range instead of Excel Read Range as it doesn’t need Excel application.
You can try filtering or querying data directly with Read Range + LINQ/DataTable.Select instead of looping all rows.
You can try splitting large files into smaller chunks or using Database/CSV import for faster processing.

3

@SR_9128,

If your file is going to be static or you are going to read the excel file once per execution, I would suggest you to use excel file as database.

Refer this how to guide by @ABHIMANYU_THITE1

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@SR_9128 , here is my suggestion:

  • Use Workbook Read Range (faster, no Excel needed)
  • Disable Preserve Formatting in Read Range
  • Specify exact ranges, don’t read entire sheet
  • Use LINQ/DataTable.Select to filter instead of looping rows
  • Process data in smaller chunks if possible
  • Prefer CSV files if Excel features aren’t needed
  • Minimize opening/closing Excel Application Scope

Hope it helps!!

5

I created a sample Studio project in the past (tested under Studio/Robot 2025.0.166).

This workflow reads a large CSV file as text, splits it into smaller batches based on the desired row count, saves each batch as a separate CSV file, and then reads each of the generated CSV files. Also performs a garbage collection and memory release before reading any new CSV file.

It should help customers when they are having very large CSV files to process and read them in a DataTable.

For the CSV with 100001 rows and 12 columns, the execution duration is 5-6 seconds.
For this sample CSV 2000000 with rows and 12 columns ( Google Drive - Virus scan warning ), it takes 3 minutes and 5 seconds.

ReadLargeCSVFile.zip (7.7 MB)

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6

Use Excel as Database for large excel files or use it as Linq