First Aid Guide

Cause: You selected the wrong mate connector. Onshape moved the part to an incorrect position.

1. Press Ctrl+Z to undo
2. Press F to fit the view back to normal
3. Redo the mate, this time carefully checking that the white dot you select is in the correct position
4. Tip: Hold Shift before selecting to lock the inferred mate connector, making it easier to pick the center of a square hole

Cause: The part orientation is flipped. Imagine inserting a LEGO brick from the bottom instead of the top.

1. No need to undo! In the mate dialog, click Flip primary axis
2. If it's still wrong, try Reorient secondary axis
3. Try different combinations of Flip and Reorient — one of them will be correct
4. There are at most 4 combinations (normal/flipped x 0°/90°), just try them all

Cause: Overconstrained — you gave Onshape contradictory instructions, like telling a part to be in two different places at once.

1. Look at the Mate Features list on the left for red/yellow marked mates
2. Right-click the problematic mate → Delete
3. Redo the mate
4. Tip: A part usually only needs one Fastened mate to be locked in place. If you created two Fastened mates for the same part, they will conflict

Cause: You selected the right type of mate connector, but picked the wrong specific point.

1. Zoom in to check if the mate connector you selected is actually where you intended
2. For example: you meant to select the center of a square hole, but may have picked a point on the edge
3. Tip: Hold Shift before selecting to lock the inferred point, making it easier to see and select
4. If unsure, click Solve to preview the result before confirming

Cause: You probably used a Fastened mate instead of a Revolute mate. Fastened = completely locked, no movement at all.

1. Find the mate in the Mate Features list on the left
2. Double-click it to edit
3. Change the type from Fastened to Revolute
4. Or: Delete the mate and create a new Revolute mate

Cause: You may have forgotten to confirm the operation, or didn't properly select an element.

1. Check if there's a dialog box waiting for you to click the green checkmark ✅
2. Check if a popup is hidden behind something — try dragging the window
3. Confirm that you selected the correct element (selected items should be highlighted)
4. Try pressing Esc to cancel the current operation, then start over

Cause: Don't worry! Onshape won't actually "break."

1. Method 1: Press Ctrl+Z many times to go back to a correct state
2. Method 2: If undo isn't enough, go to the History to revert to a previous version
3. Method 3: Copy a fresh version from the original document and start from scratch (Document menu → Copy workspace)
4. Remember: Create Version snapshots frequently so you can always return to a "save point"