.ASO file extension

To open .ASO files on Windows, check the source of the file: NCBI/GenBank files are usually scientific data, while bank/accounting files may be Sage or Simply Accounting exports.

To open a .ASO file, first identify where it came from. GenBank/NCBI .ASO files should be processed with NCBI DATATOOL, while bank or accounting .ASO files are typically OFX-style exports for Simply Accounting or Sage accounting software.

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Last updated: April 29, 2026 · Reviewed by Julian Stricker

Open on your device

Choose your operating system for a dedicated step-by-step opening guide.

How to open .ASO files

Use these platform-specific instructions to open .ASO files safely.

Windows

Check the source of the file: NCBI/GenBank files are usually scientific data, while bank/accounting files may be Sage or Simply Accounting exports.
For NCBI GenBank .ASO files, use NCBI DATATOOL to convert or process the binary ASN.1 data.
For accounting .ASO files, open or import the file in Simply Accounting or compatible Sage accounting software if that is the system that produced the export.
If the file ends in .aso.gz, decompress the .gz file first, then process the resulting .aso file.

Full Windows guide

Mac

Control-click the file and choose Get Info or inspect the filename and source to determine whether it is NCBI data or an accounting export.
For NCBI data, use NCBI DATATOOL or transfer the file to a desktop environment where the NCBI tools are installed.
For accounting exports, use the accounting application or online banking workflow that generated the .ASO file; macOS has no general built-in .ASO viewer.
If the file is compressed as .aso.gz, decompress it before opening or converting it.

Full Mac guide

Linux

Use the filename and source to identify the type; GenBank release files often have names like gbpri1.aso or may arrive as .aso.gz.
For NCBI files, run NCBI DATATOOL or other NCBI Toolkit-based workflows to convert or process the binary ASN.1 data.
For .aso.gz files, decompress with gzip/gunzip first, then process the resulting .aso file.
Accounting .ASO files are not generally handled natively on Linux; import them in the intended accounting software or transfer them to a supported desktop.

Full Linux guide

iOS

iOS does not have native support for NCBI binary ASN.1 or Simply Accounting .ASO files; save the file in Files and transfer it to a desktop system with the correct software.
Do not rename the file to .ofx or another extension unless the exporting bank or accounting software specifically instructs you to do so.

Full iOS guide

Android

Android does not usually include an app that can use .ASO files directly; download the file only if you plan to transfer it to the correct desktop tool.
If the file is an accounting export, import it through the intended accounting software rather than opening it in a generic viewer.

Full Android guide

Security notes

.ASO accounting files can contain sensitive financial account and transaction information; store and share them as confidential data.
Do not import .ASO accounting files from unknown senders, because they may alter accounting records if accepted by your bookkeeping software.
NCBI .ASO files are binary data parsed by specialized scientific software; use up-to-date tools when processing files from untrusted or unfamiliar sources.
Compressed .aso.gz files should be decompressed only after confirming the source and expected filename, especially when obtained from mirrors or archives.

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Can't open this file?

These are the most common causes and fixes when .ASO files fail to open.

Common reasons

The file opens as unreadable text or gibberish
The wrong application tries to open the file
The file is still compressed
Accounting import fails

Fix steps

Confirm whether the file came from NCBI or a GenBank distribution.
Use NCBI DATATOOL to convert or process the file instead of opening it as plain text.
If the file is .aso.gz, decompress it first and then run the conversion.

OS-specific troubleshooting

What is a .ASO file?

.ASO is not one single universal format. NCBI uses .aso for GenBank data in binary ASN.1 format, often distributed as files such as gbpri1.aso or as compressed .aso.gz files. Separately, IANA registers application/vnd.accpac.simply.aso for .ASO files used by Simply Accounting v7.0 and higher, conforming to OFX 1.02.

Background

.ASO files are usually encountered in two professional contexts. In bioinformatics, NCBI documents .ASO files as binary ASN.1 GenBank data files, including Bioseq-set release files. These are not meant to be opened like documents; they are normally converted or processed with NCBI tools such as DATATOOL.

Common MIME types: chemical/x-ncbi-asn1-binary

Common .ASO issues

The file opens as unreadable text or gibberish

NCBI .ASO files are binary ASN.1 data, so a normal text editor will not display meaningful content.

Confirm whether the file came from NCBI or a GenBank distribution.
Use NCBI DATATOOL to convert or process the file instead of opening it as plain text.
If the file is .aso.gz, decompress it first and then run the conversion.

The wrong application tries to open the file

.ASO is used by more than one workflow, so the operating system may associate it with the wrong program or with no program at all.

Identify whether the file is scientific NCBI data or an accounting OFX-style export.
Use Open With to choose NCBI DATATOOL-related processing for GenBank data or the appropriate Simply Accounting/Sage workflow for accounting data.
Avoid changing the file extension as a shortcut; it does not convert the file.

The file is still compressed

NCBI release files are often distributed with a .aso.gz suffix, meaning the .ASO file is inside a gzip-compressed file.

Decompress the .gz file with a gzip-compatible tool.
Verify that the extracted file ends in .aso.
Process the extracted .aso file with the NCBI toolchain.

Accounting import fails

Some .ASO files are Simply Accounting/Sage OFX exports, and import can fail if the file was downloaded for the wrong account, changed after export, or opened in software that does not support that workflow.

Download the export again from the bank or accounting portal.
Do not edit the file manually unless instructed by the accounting software vendor.
Import it using the Simply Accounting or Sage workflow that the bank documents for .ASO files.

FAQ

Is every .ASO file an NCBI GenBank file?

No. NCBI uses .ASO for binary ASN.1 GenBank data, but .ASO is also registered for Simply Accounting OFX-style accounting files.

Can I open a .ASO file in a text editor?

Usually not usefully. NCBI .ASO files are binary ASN.1 and will look unreadable; accounting .ASO files may be structured financial data, but they should normally be imported rather than edited.

What should I do with a .aso.gz file?

A .aso.gz file is gzip-compressed. Decompress it first, then use the resulting .aso file with the appropriate NCBI processing tool.

What MIME types are associated with .ASO?

Sources list chemical/x-ncbi-asn1-binary for NCBI ASN.1 data and application/vnd.accpac.simply.aso for Simply Accounting .ASO files.

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