How to restore a fragmented backup

A very large sketchup model - 400Mb - was fragmented into 6 parts in a backup (6 files with exactly the same name, but differing file sizes).
The various parts are now either ‘unexpected file format’ or ‘not a sketchup model’.

Does anyone know if the parts can be recombined?

Thanks for any help.

Isn’t this a question for the backup software vendor rather than SU?


Thanks for that. Yes, that would be correct if I still had the backup software. However, I upgraded from Windows Vista to 8.1 and lost the backup support. So I guess asking the Sketchup Community is a kind of last resort.

Hi @liam_hennessy_arch,

Sadly that is definitely something that will be controlled by the backup software as the backup software would contain the “key” telling each piece how they go together. Sadly, even if you’ve put them back together and have a single 400 Mb SKP file with the “Invalid File Format” we historically don’t have great success recovering all of the data, especially in something that size.

If I were working with a file that large I would endeavour to be keeping multiple backups while working on it, backing up each day’s results to a new file and purging the old stuff every week so you’d have your working drawing and a 1 backup per day for the last n days (probably 3 or 5) to avoid losing any data.

I hope you can find a way to get your backup software working, that sounds like it could be a lot of re-work to rebuild.

Good luck!

Hi Jody

Yes, I realise that I have to do more on the software side. I have now written to Seagate (software backup) to see if they have any suggestions. I will let you know what they say.
Clearly I was not careful enough in keeping multiple copies, especially as the model grew to be so large. Luckily I gave a copy to a colleague about 5 weeks before the final backup, but I may have lost the work done during that 5 week period - quite a lot.
So it will be a significant headache, but not a total disaster. Fortunately I do have the majority of the model, by chance rather than by proper housekeeping.
But for the future, keeping multiple and frequent copies of so large a model will be essential.

Many thanks for your help.