Flows lost ; where are they gone?

hello
I was working with nodered for some month, and suddenly, my flows have disappeared.
It seems that one node or one flow makes node-red crash.
I can see it when i run node-red manually.
Ok, I can understand this, even if I didn't make no chnage in the involved node
But what is strange is that my flows have disappeared.
In my flows, there are some notofications wich are sent by IFTTT and a mail, also.
I receive the notification and the mail. so that means that my flows are still in may machine
but when I try to access to the node-red interface, by starting node-red with the comman --safe mode, to be sure that no flow is started, it works
But unfirtunately, I can see no more flow in the :1880 web interface.
How can it be?
Where are my flows?
How can I get them back on the node-red web interface?
I use :slight_smile:

1 Sep 22:42:59 - [info] Node-RED version: v0.20.5
1 Sep 22:42:59 - [info] Node.js  version: v10.15.3
1 Sep 22:42:59 - [info] Linux 4.14.63-rt40-pxc arm LE