2fa window crashing when tried to load 2fa file

[creativecoder-0717]

I reinstalled my laptop system and 2fa authenticator app too. When I tried to load my 2fa file, it showed loading. but, after 5 - 10 seconds, unexpectedly windows crashed.
I repeated several times but same thing happened.

Error message is like this.

System.Exception: Exception of type 'System.Exception' was thrown. Unexpected character encountered while parsing value: <. Path", line 0, position 0.

I have to solve this problem urgently. Just hope to help me.

[jp-weber]

Have you tried to open the .2fa file via double click? Have you tried to reinstall the app again?

The log entry would be useful to narrow down the potential problem.
The log is accessible as a menu item via settings/functions or via cmd: https://github.com/2fast-team/2fast/wiki/Open-(error)-log-via-cmd

or via explorer:
When the AppLog.log is created, the file is saved in the local folder:

%LOCALAPPDATA%\Packages\38343JanPhilippWeber.2fastTwoFactorAuthenticatorSu_nxr4mypqfqb9c\LocalState

[creativecoder-0717]

2025-11-02 19:50:59 - uptime -10675199.02:48:05.4775808
2025-11-02 19:50:59 - - Unexpected character encountered while parsing value: <. Path '', line 0, position 0.
Log - Newtonsoft.Json.JsonReaderException: Unexpected character encountered while parsing value: <. Path '', line 0, position 0.
at Newtonsoft.Json.JsonTextReader.ParseValue() + 0x36e
at Newtonsoft.Json.JsonTextReader.Read() + 0x52
at Newtonsoft.Json.JsonReader.ReadAndMoveToContent() + 0x11
at Newtonsoft.Json.JsonReader.ReadForType(JsonContract, Boolean) + 0x56
at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader, Type, Boolean) + 0x239
at Newtonsoft.Json.JsonSerializer.DeserializeInternal(JsonReader, Type) + 0xf3
at Newtonsoft.Json.JsonConvert.DeserializeObject(String, Type, JsonSerializerSettings) + 0xd6
at Newtonsoft.Json.JsonConvert.DeserializeObjectT + 0x32
at Project2FA.Core.Services.JSON.NewtonsoftJSONService.DeserializeT + 0x42
at Project2FA.ViewModels.FileActivationPageViewModel.d__19.MoveNext() + 0x20c

When I typed "%LOCALAPPDATA%\Packages\38343JanPhilippWeber.2fastTwoFactorAuthenticatorSu_nxr4mypqfqb9c\LocalState"
Above text was displayed, and I think there is some parsing issue.
When I created new 2fa file in current new system, it works well. I can add accounts and do everything.
Even when I typed wrong password, it said wrong credential.
But when I tried to open old OS 2fa file, it does not work. and just blank password field display again and again. I mean password field become refresh and nothing open.

Is this due to computer OS update? if so how to fix this issu? 2Fa file contains sensitive gmail related info. So this is essential to me