I've no idea what happened here. I've setup a LOT of custom dialogue, complete guard dialogue for every occasion (bribe, go to jail, idles, hellos, goodbyes, EVERYTHING), also lots on NPC dialogue, has taken me months to do this. For the past week I've been concentrating on an interior cell, nothing related to quests, actors, factions or dialogue. Just called it a day and decided to go and wander around my world. Not 1 NPC says any custom dialogue. The guards don't say anything at all even when clicked on, their entire vocabulary is custom and now it's gone. I don't get this at all. Why does CK do tricks like this? I've a good mind to just give up on the whole project if nobody can help me, please, restore what I had, it is way too much work to go through dialogue line by line again.

Absolutely at my wits end with CK, advice PLEASE!!!

Apart from the advice you already know you were forgetting, to keep making regular copies of all your work, have you looked in Skyrim\Backup folder? By default the CK should have been making intermittent backups in there. You might be able to use TES5Edit to compare your non-working mod with an old working backup and see what (apart from that interior) has changed.

I'll look it over tomorrow, really has put in a mood this has. I make backups to usb every couple of days but problem is I don't know when this issue began. As I said I've been working on an Epic interior cell for a while, over a week which means the backups I made, last being 2 days ago, more than likely have the same issue.

Honestly thinking about giving it all up, thanks for the suggestion.

If you don't have backups, you could try regenerating your .seq file.

I remade the Seq. and it managed to get the text displayed on screen but no voice. I've been through almost everything and the only "repair" I can make is this one. Guards have many factions and I based their dialogue/quest on the conditions GetInFaction MyGuardFaction==1. Now thankfully I made a unique Voice Type for them, so I changed the condition to GetIsVoiceType. I recorded some silence basically to see where CK would put the file. It made a new folder and a new voice type folder within it. I then copied all the guards .wav files from the old folder to the new which CK had just made. Again thankfully the file names were preserved for the dialogues, so the game now only looks in that folder for the voice. Now guards are "talking" I have to make unique voices for every race in my mod, copy over existing voice files, check file names are correct and go chat to them all. Not as long-winded/problematic as I had expected. Now my main concern is that it will happen again for no reason and I'll end up fixing it again. I just don't get it, why did this happen?

I noted that I only have .wav files for voices, previously I had .wavs and made .xwms for each as well. For actors to speak they only need the .wav file and to create a .lip file only the .wav is needed (guards don't use .lip as they wear helmets). So is the only reason for the .xwm file for when making the final .fuz files?

.xwm files are just much smaller files than .wav. That's the main reason for making .xwm files at all as far as I know.