Math formula is empty

Hi there,

I am using Ubuntu 20 with lo While working on a document build under an older lo version I encounter a strange behaviour:

I can view all my embedded math formula, but when I try to open and reddit it, the formula clears. This cannot be recovered.

Any help is appreciated.

Lars Peer

See example file: (most formulas behave like told)


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Please see edited question above, Thx

While working on a document build under an older lo version I encounter a strange behaviour

I see the problem locally, using Version: (x64) / LibreOffice Community
Build ID: 8a45595d069ef5570103caea1b71cc9d82b2aae4
CPU threads: 12; OS: Windows 10.0 Build 19042; UI render: Skia/Raster; VCL: win
Locale: ru-RU (ru_RU); UI: en-US
Calc: CL.

But examining the formula data in the document, it has totally wrong XML - starting with wrong root element name.

E.g., /Object 158/content.xml:

<?xml version="1.0" encoding="UTF-8"?>
<matrix-covered xmlns=""

must have been:

<?xml version="1.0" encoding="UTF-8"?>
<math xmlns=""

It was generated using a broken generator.

I remember we had a problem like this once - a bug made some XML elements “shifted”. I suppose that this document can only be recovered by opening the ODT, and manually replacing relevant element names with correct names.

I used (I hope this is an old enough version) to display your file. Same issue. The XML shows the description of the formula is empty or contains varying number of {. Writer uses the embedded equivalent picture to display the formula.

I see the same on y Windows 10 machine with your file.

To retrieve the formulas without retyping all, make a copy of the file and open it with an archive manager. Then go to the /Object xxx folders and open the contents.xml file. At the end, you can copy the formula code (highlighted below) and paste it in a new formula to replace the former one:

To be done for each formula…

It may be worth a bug report to highlight this retro-compatibility issue.

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Unfortunately, this is not a retro-compatibility issue, it is a bug in the version used for generation of the document… It created a file broken for both earlier and later versions.

I wrote “unfortunately”, because this way, it’s impossible to “fix” the bug in a way that the file would read correctly in current versions. But I seem to remember that that bug was in a “early adopter” version (like X.Y.0 or X.Y.1); yet, I may be mistaken.

Thanks for the clarification!

Another point against the use of fresh versions for production work.