I mixed SLIP-39 shares from different sets and now I can't restore
You assumed any SLIP-39 share would work with any other, and now the wallet won't let you continue.
**SLIP-39 shares from two different sets don't combine, even if you use the same scheme and they look identical.**
Shares are not interchangeable
Each SLIP-39 backup creates a set with its own internal identifier. A share only works with others from that same set.
The source puts it literally: "shares from different sets are incompatible even if they use the same scheme" (SLIP-0039, Extendable Backup section). Even if the words look identical, shares from different sets won't combine.
If you already mixed them
Stop trying random combinations. A failed attempt doesn't break anything, but it wastes time and makes the confusion worse.
Go back to your original notes and separate shares by set. If you don't know which share belongs to which set, the fix is to rebuild the correct set, not to force the mix.
Label each share clearly
Write on each share which set it belongs to: wallet name, date, or a set identifier. Don't rely on them looking similar; a share from another backup won't save you.
What this does not say about SLIP-39
This doesn't make SLIP-39 fragile. The risk is mixing sets, not the scheme itself. It's not a reason to avoid SLIP-39; it's a reason to label each share well.
What this does not say about SLIP-39
This doesn't make SLIP-39 fragile. The risk is mixing sets, not the scheme itself. It's not a reason to avoid SLIP-39; it's a reason to label each share well.
Source: SLIP-0039, seccion Extendable Backup