Open Excel doc and save

When I open (from my Android device) a “Cryptomated” excel file that lives in OneDrive, it opens as Read-Only, and accordingly, I can’t edit it.

Is there a way to do this?


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Hey and welcome in the community :slight_smile:!

Unfortunately this is a known problem.
Here you can read more about it:

Unfortunately we can’t do anything without reducing the security of our app. Microsoft must patch their applications :frowning_face:

Edit: You can still edit these files by exporting, opening and uploading it after changing to the vault. Not convenient, I know :face_vomiting:

Thanks for the quick reply. I took a look at the link you provided. I can open/save docs with Boxcryptor, so I don’t completely understand the distinction.

That is right, I’ll try to explain what the difference is.

Under the path Android/data/ every app can have a app specific public folder. This folder can access every app with storage access permission.

If you open a file using e.g. Boxcryptor, after and while you opened it in e.g. Excel, using your file browser navigate into the following directory Android/data/
After opening the file, a new folder was created with a generic id and inside this folder, you can find your decrypted Excel-file. Because of moving this file into the public space, Microsoft apps can access this file with write permission. As I found out in , this is the only way to open the file in Microsoft apps with write access. But every other app with storage access permission like your file browser or your flashlight can access this decrypted file as well…

Because of this, we decided to accept the problem with the Microsoft apps instead of also moving our files after decryption into the public space and hope, that Microsoft will fix their apps because there is no reason why the files from the internal app specific folder cannot be opened with write permission (other apps are able to do this without problems).

A workaround to tackle the problem could be to leave it up to the user where the files are stored, similar to what Nextcloud does but with a clear indication of the advantages and problems of each location e.g. security vulnerability:

Then the user can decide if he wants to give up security and write directly using ms apps. But this is rather a crutch and I personally would never activate it, even if I only have apps on my device that I trust.

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I found two ways to actually open, edit and save Excel files
(and propably Office files) within Cryptomator Android.

The two methods work perfectly for me.
Second Method is simpler and faster.


You open in Excel app
It says " read only … you can’t save changes …"

Actually it is not true.

First, file can be edited, so it’s not “read only”
Second, it can be saved, yes. So you “can save changes”.

So you edit the Excel file and when you are done
you choose the “share ICON” on top right corner
Then “share as attachment”
Choose “Workbook”
In app list choose the Cryptomator app
on my phone it is “encrypt” with the Cryptomator logo.
Then you can access Cryptomator and replace-save
over the file with the same name.


You don’t need Office Excel for Android to open Excel files on Android.
You can use : OfficeSuite, Polaris Office, WPS, …

I have tried all of those and OfficeSuite worked to open, edit, save, with Cryptomator.(not the others). I also found OfficeSuite better quality …

So with OfficeSuite installed, within Cryptomator
just open with OfficeSuite, edit, save.


I personally use OneSync to sync my local Cryptomated files on Android,

Just after editing-saving my Excel file Cryptomator encrypts it,
OneSync detects the changes and sends it to OneDrive.
1 minute after the Cryptomated Excel file is on my home computer …


Does Excel or any other app leaves un-encrypted temp files
somewhere when we open and edit an Excel file ?
I personally don’t now.

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