🛑 What you’re seeing
When you go to File > Open, your model list appears to be a bunch of scrambled letters and symbols.
Your model list will look a bit like this when you go to File > Open:
🔎 What it usually means
In our experience, the file is now completely corrupted and beyond recovery.
It is not clear why this happens, but you need to be aware that a CAD file is simply a series of zeros and ones called 'bits', assembled in groups of eight call 'bytes'. All it takes is one of the 'bits' to get lost among the millions of other 'bits', and the entire structure is lost. The file is now corrupt.
Programmers go to a lot of trouble to ensure that this doesn't occur by devising a raft of tools to check the integrity of the data as it is written, transferred, copied and saved etc. However, the odds are that sooner or later you will get a 'wrinkle' in the network that messes up the data structure, with this as just one example of how it presents.
There is typically nothing you can do to recover a file as badly corrupted as this.
💾 Why backups are essential
This is why it is essential that you have a well established back up procedure and that this procedure is religiously applied and checked on a regular basis.
A data back up is NOT AN OPTION!
If you have an IT department or dedicated person, make sure that they have a backup procedure in place and that they test it regularly to ensure that it is actually backing up. Sounds like a redundent request, but we know of quite a few instances where everyone thought the back up was happening, only to discover (when they needed it) that in actual fact nothing was being backed up. The process was broken and no-one had checked it for weeks.
If you do not have an IT department consider simply copying all your jobs in the ..\User folder to a memory stick/thumb drive. You might do this daily, alternate days, weekly or every day ending in 'Y'. It only takes a minute and will save you hours, even days rebuilding lost information.
At the end of the day, ask yourself this - "how much work do I want to redo if I have a hardware failure and the data gets lost or corrupted?". This tells you how frequently you should be backing up.
Also take account of the fact that if your IT department sets up a system to back up your work, and that fails - you are the 'bunny' stuck with redoing all the lost work.
Take charge of backing up your own stuff!
🧰 One recovery utility you can try (sometimes works)
There is one utility we have created that sometimes works to recover lost data, but the sort of error displayed above is usually beyond recovery, even usung this method.
If you get a result like this (below) and you know it is a lost cause, go to the latest back up file.
The utility writes a transfer file (*.tra) which attempts to re-construct the data. You write the TRA file and then read it back.
The function is found at:
CAD > File > WR-Trans to write the file
CAD > File > Rd-Trans to attempt to read it back
