[Eeglablist] Version 2026 bug? Unable to rereference to the average reference and add back online ref

[Arnaud Delorme]

Hi Kelsey,

There is no issue that we know of.
Would you mind creating an issue and linking a dataset along with instructions to recreate the problem?

https://urldefense.com/v3/__https://github.com/sccn/eeglab/issues__;!!Mih3wA!A0b1Igjj4mAqHEgZjT7A38Z5LTLCPA7cOoirm9CIPkFj4rxNGT8S8QcXMwux8cFhoN2prwBAMJ6iE03zBKN2fZIg$ 

Arno

> On May 18, 2026, at 09:22, Kelsey Frewin (PSY - Staff) via eeglablist <eeglablist at sccn.ucsd.edu> wrote:
> 
> Hi,
> 
> I’m wondering if anyone else is experiencing issues with re-referencing recently? I’ve recently upgraded my MATLAB version (although this issue occurs whether I’m using 2023b, 2024b or 2025b) and my EEGLAB version (2026 – I’m on a Mac.
> 
> I’ve been using this same pipeline with the same data for the past 2 years with no issues and since the upgrade I’m unable to re-reference to average reference and add back the online reference channel because I get the following error:
> 
> Error using pop_reref (line 393)
> Missing reference channel information. Edit channels and add reference first.
> 
> This happens whether I use script or the GUI. But before running, I always confirm the reference channel info is present. Prior to this, I’ve appended the online ref, looked up channel locations, set the ref and checked the set:
> 
> % add channel for the online reference (FCz)
> EEG=pop_chanedit(EEG, 'append',63,'changefield',{64,'labels','FCz'});
> 
> % find channel location
> EEG = pop_chanedit(EEG, 'lookup', filechanloc);
> 
> % set FCz as reference (to be added as a channel when re referenced
> EEG = pop_chanedit(EEG, 'setref',{'1:64','FCz'});
> 
> EEG = eeg_checkset(EEG);
> 
> My colleague in the same lab has been able to recreate the issue on a Windows device and I’ve now spoken to colleagues in other labs experiencing the same issue at the moment. Has something changed in the recent EEGLAB version that is preventing this?
> 
> Thanks,
> 
> Kelsey
> 
> Dr Kelsey Frewin (she/her)
> Postdoctoral Researcher
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